The Mark of Athena

She headed back to the hole in the mosaic floor. She secured one end of her ladder to the nearest piece of scaffolding, lowered the rope into the cavern, and shinnied down.

AS ANNABETH HUNG IN THE AIR, descending hand over hand with the ladder swinging wildly, she thanked Chiron for all those years of training on the climbing course at Camp Half-Blood. She’d complained loudly and often that rope climbing would never help her defeat a monster. Chiron had just smiled, like he knew this day would come.

Finally Annabeth made it to the bottom. She missed the brickwork edge and landed in the canal, but it turned out to be only a few inches deep. Freezing water soaked into her running shoes.

She held up her glowing dagger. The shallow channel ran down the middle of a brickwork tunnel. Every few yards, ceramic pipes jutted from the walls. She guessed that the pipes were drains, part of the ancient Roman plumbing system, though it was amazing to her that a tunnel like this had survived, crowded underground with all the other centuries’ worth of pipes, basements, and sewers.

A sudden thought chilled her even more than the water. A few years ago, Percy and she had gone on a quest in Daedalus’s labyrinth—a secret network of tunnels and rooms, heavily enchanted and trapped, which ran under all the cities of America.

When Daedalus died in the Battle of the Labyrinth, the entire maze had collapsed—or so Annabeth believed. But what if that was only in America? What if this was an older version of the labyrinth? Daedalus once told her that his maze had a life of its own. It was constantly growing and changing. Maybe the labyrinth could regenerate, like monsters. That would make sense. It was an archetypal force, as Chiron would say—something that could never really die.

If this was part of the labyrinth…

Annabeth decided not to dwell on that, but she also decided not to assume her directions were accurate. The labyrinth made distance meaningless. If she wasn’t careful, she could walk twenty feet in the wrong direction and end up in Poland.

Just to be safe, she tied a new ball of string to the end of her rope ladder. She could unravel it behind her as she explored. An old trick, but a good one.

She debated which way to go. The tunnel seemed the same in both directions. Then, about fifty feet to her left, the Mark of Athena blazed against the wall. Annabeth could swear it was glaring at her with those big fiery eyes, as if to say, What’s your problem? Hurry up!

She was really starting to hate that owl.

By the time she reached the spot, the image had faded, and she’d run out of string on her first spool.

As she was attaching a new line, she glanced across the tunnel. There was a broken section in the brickwork, as if a sledgehammer had knocked a hole in the wall. She crossed to take a look. Sticking her dagger through the opening for light, Annabeth could see a lower chamber, long and narrow, with a mosaic floor, painted walls, and benches running down either side. It was shaped sort of like a subway car.

She stuck her head into the hole, hoping nothing would bite it off. At the near end of the room was a bricked-off doorway. At the far end was a stone table, or maybe an altar.

Hmm…The water tunnel kept going, but Annabeth was sure this was the way. She remembered what Tiberinus had said: Find the altar of the foreign god. There didn’t seem to be any exits from the altar room, but it was a short drop onto the bench below. She should be able to climb out again with no problem.

Still holding her string, she lowered herself down.

The room’s ceiling was barrel-shaped with brick arches, but Annabeth didn’t like the look of the supports. Directly above her head, on the arch nearest to the bricked-in doorway, the capstone was cracked in half. Stress fractures ran across the ceiling. The place had probably been intact for two thousand years, but she decided she’d rather not spend too much time here. With her luck, it would collapse in the next two minutes.

The floor was a long narrow mosaic with seven pictures in a row, like a time line. At Annabeth’s feet was a raven. Next was a lion. Several others looked like Roman warriors with various weapons. The rest were too damaged or covered in dust for Annabeth to make out details. The benches on either side were littered with broken pottery. The walls were painted with scenes of a banquet: a robed man with a curved cap like an ice cream scoop, sitting next to a larger guy who radiated sunbeams. Standing around them were torchbearers and servants, and various animals like crows and lions wandered in the background. Annabeth wasn’t sure what the picture represented, but it didn’t remind her of any Greek legends that she knew.

At the far end of the room, the altar was elaborately carved with a frieze showing the man with the ice-cream-scoop hat holding a knife to the neck of a bull. On the altar stood a stone figure of a man sunk to his knees in rock, a dagger and a torch in his outraised hands. Again, Annabeth had no idea what those images meant.

She took one step toward the altar. Her foot went CRUNCH. She looked down and realized she’d just put her shoe through a human rib cage.

Annabeth swallowed back a scream. Where had that come from? She had glanced down only a moment before and hadn’t seen any bones. Now the floor was littered with them. The rib cage was obviously old. It crumbled to dust as she removed her foot. Nearby lay a corroded bronze dagger very much like her own. Either this dead person had been carrying the weapon, or it had killed him.

She held out her blade to see in front of her. A little farther down the mosaic path sprawled a more complete skeleton in the remains of an embroidered red doublet, like a man from the Renaissance. His frilled collar and skull had been badly burned, as if the guy had decided to wash his hair with a blowtorch.

Wonderful, Annabeth thought. She lifted her eyes to the altar statue, which held a dagger and a torch.

Some kind of test, Annabeth decided. These two guys had failed. Correction: not just two guys. More bones and scraps of clothing were scattered all the way to the altar. She couldn’t guess how many skeletons were represented, but she was willing to bet they were all demigods from the past, children of Athena on the same quest.

“I will not be another skeleton on your floor,” she called to the statue, hoping she sounded brave.

A girl, said a watery voice, echoing through the room. Girls are not allowed.

A female demigod, said a second voice. Inexcusable.

The chamber rumbled. Dust fell from the cracked ceiling. Annabeth bolted for the hole she’d come through, but it had disappeared. Her string had been severed. She clambered up on the bench and pounded on the wall where the hole had been, hoping the hole’s absence was just an illusion, but the wall felt solid.

She was trapped.

Along the benches, a dozen ghosts shimmered into existence—glowing purple men in Roman togas, like the Lares she’d seen at Camp Jupiter. They glared at her as if she’d interrupted their meeting.

She did the only thing she could. She stepped down from the bench and put her back to the bricked-in doorway. She tried to look confident, though the scowling purple ghosts and the demigod skeletons at her feet made her want to turtle in her T-shirt and scream.

“I’m a child of Athena,” she said, as boldly as she could manage.

“A Greek,” one of the ghosts said with disgust. “That is even worse.”

At the other end of the chamber, an old-looking ghost rose with some difficulty (do ghosts have arthritis?) and stood by the altar, his dark eyes fixed on Annabeth. Her first thought was that he looked like the pope. He had a glittering robe, a pointed hat, and a shepherd’s crook.

“This is the cavern of Mithras,” said the old ghost. “You have disturbed our sacred rituals. You cannot look upon our mysteries and live.”

“I don’t want to look upon your mysteries,” Annabeth assured him. “I’m following the Mark of Athena. Show me the exit, and I’ll be on my way.”

Her voice sounded calm, which surprised her. She had no idea how to get out of here, but she knew she had to succeed where her siblings had failed. Her path led farther on—deeper into the underground layers of Rome.

The failures of your predecessors will guide you, Tiberinus had said. After that…I do not know.

The ghosts mumbled to each other in Latin. Annabeth caught a few unkind words about female demigods and Athena.

Finally the ghost with the pope hat struck his shepherd’s crook against the floor. The other Lares fell silent.

“Your Greek goddess is powerless here,” said the pope. “Mithras is the god of Roman warriors! He is the god of the legion, the god of the empire!”

“He wasn’t even Roman,” Annabeth protested. “Wasn’t he, like, Persian or something?”

“Sacrilege!” the old man yelped, banging his staff on the floor a few more times. “Mithras protects us! I am the pater of this brotherhood—”

“The father,” Annabeth translated.

“Do not interrupt! As pater, I must protect our mysteries.”

“What mysteries?” Annabeth asked. “A dozen dead guys in togas sitting around in a cave?”

The ghosts muttered and complained, until the pater got them under control with a taxicab whistle. The old guy had a good set of lungs. “You are clearly an unbeliever. Like the others, you must die.”

The others. Annabeth made an effort not to look at the skeletons.

Her mind worked furiously, grasping for anything she knew about Mithras. He had a secret cult for warriors. He was popular in the legion. He was one of the gods who’d supplanted Athena as a war deity. Aphrodite had mentioned him during their teatime chat in Charleston. Aside from that, Annabeth had no idea. Mithras just wasn’t one of the gods they talked about at Camp Half-Blood. She doubted the ghosts would wait while she whipped out Daedalus’s laptop and did a search.

She scanned the floor mosaic—seven pictures in a row. She studied the ghosts and noticed all of them wore some sort of badge on their toga—a raven, or a torch, or a bow.

“You have rites of passage,” she blurted out. “Seven levels of membership. And the top level is the pater.”

The ghosts let out a collective gasp. Then they all began shouting at once.

“How does she know this?” one demanded.

“The girl has gleaned our secrets!”

“Silence!” the pater ordered.

“But she might know about the ordeals!” another cried.

“The ordeals!” Annabeth said. “I know about them!”

Another round of incredulous gasping.

“Ridiculous!” The pater yelled. “The girl lies! Daughter of Athena, choose your way of death. If you do not choose, the god will choose for you!”

“Fire or dagger,” Annabeth guessed.

Even the pater looked stunned. Apparently he hadn’t remembered there were victims of past punishments lying on the floor.

“How—how did you… ?” He gulped. “Who are you?”

“A child of Athena,” Annabeth said again. “But not just any child. I am…uh, the mater in my sisterhood. The magna mater, in fact. There are no mysteries to me. Mithras cannot hide anything from my sight.”

“The magna mater!” a ghost wailed in despair. “The big mother!”

“Kill her!” One of the ghosts charged, his hands out to strangle her, but he passed right through her.

“You’re dead,” Annabeth reminded him. “Sit down.”

The ghost looked embarrassed and took his seat.

“We do not need to kill you ourselves,” the pater growled. “Mithras shall do that for us!”

The statue on the altar began to glow.

Annabeth pressed her hands against the bricked-in doorway at her back. That had to be the exit. The mortar was crumbling, but it was not weak enough for her to break through with brute force.

She looked desperately around the room—the cracked ceiling, the floor mosaic, the wall paintings, and the carved altar. She began to talk, pulling deductions from the top of her head.

“It is no good,” she said. “I know all. You test your initiates with fire because the torch is the symbol of Mithras. His other symbol is the dagger, which is why you can also be tested with the blade. You want to kill me, just as…uh, as Mithras killed the sacred bull.”

It was a total guess, but the altar showed Mithras killing a bull, so Annabeth figured it must be important. The ghosts wailed and covered their ears. Some slapped their faces as if to wake up from a bad dream.

“The big mother knows!” one said. “It is impossible!”

Unless you look around the room, Annabeth thought, her confidence growing.

She glared at the ghost who had just spoken. He had a raven badge on his toga—the same symbol as on the floor at her feet.

“You are just a raven,” she scolded. “That is the lowest rank. Be silent and let me speak to your pater.”

The ghost cringed. “Mercy! Mercy!”

At the front of the room, the pater trembled—either from rage or fear, Annabeth wasn’t sure which. His pope hat tilted sideways on his head like a gas gauge dropping toward empty. “Truly, you know much, big mother. Your wisdom is great, but that is all the more reason why you cannot leave. The weaver warned us you would come.”

“The weaver…” Annabeth realized with a sinking feeling what the pater was talking about: the thing in the dark from Percy’s dream, the guardian of the shrine. This was one time she wished she didn’t know the answer, but she tried to maintain her calm. “The weaver fears me. She doesn’t want me to follow the Mark of Athena. But you will let me pass.”

“You must choose an ordeal!” the pater insisted. “Fire or dagger! Survive one, and then, perhaps!”

Annabeth looked down at the bones of her siblings. The failures of your predecessors will guide you.

They’d all chosen one or the other: fire or dagger. Maybe they’d thought they could beat the ordeal. But they had all died. Annabeth needed a third choice.

She stared at the altar statue, which was glowing brighter by the second. She could feel its heat across the room. Her instinct was to focus on the dagger or the torch, but instead she concentrated on the statue’s base. She wondered why its legs were stuck in stone. Then it occurred to her: maybe the little statue of Mithras wasn’t stuck in the rock. Maybe he was emerging from the rock.

“Neither torch nor dagger,” Annabeth said firmly. “There is a third test, which I will pass.”

“A third test?” the pater demanded.

“Mithras was born from rock,” Annabeth said, hoping she was right. “He emerged fully grown from the stone, holding his dagger and torch.”

The screaming and wailing told her she had guessed correctly.

“The big mother knows all!” a ghost cried. “That is our most closely guarded secret!”

Then maybe you shouldn’t put a statue of it on your altar, Annabeth thought. But she was thankful for stupid male ghosts. If they’d let women warriors into their cult, they might have learned some common sense.

Annabeth gestured dramatically to the wall she’d come from. “I was born from stone, just as Mithras was! Therefore, I have already passed your ordeal!”

“Bah!” the pater spat. “You came from a hole in the wall! That’s not the same thing.”

Okay. So apparently the pater wasn’t a complete moron, but Annabeth remained confident. She glanced at the ceiling, and another idea came to her—all the details clicking together.

“I have control over the very stones.” She raised her arms. “I will prove my power is greater than Mithras. With a single strike, I will bring down this chamber.”

The ghosts wailed and trembled and looked at the ceiling, but Annabeth knew they didn’t see what she saw. These ghosts were warriors, not engineers. The children of Athena had many skills, and not just in combat. Annabeth had studied architecture for years. She knew this ancient chamber was on the verge of collapse. She recognized what the stress fractures in the ceiling meant, all emanating from a single point—the top of the stone arch just above her. The capstone was about to crumble, and when that happened, assuming she could time it correctly…

“Impossible!” the pater shouted. “The weaver has paid us much tribute to destroy any children of Athena who would dare enter our shrine. We have never let her down. We cannot let you pass.”

“Then you fear my power!” Annabeth said. “You admit that I could destroy your sacred chamber!”

The pater scowled. He straightened his hat uneasily. Annabeth knew she’d put him in an impossible position. He couldn’t back down without looking cowardly.

“Do your worst, child of Athena,” he decided. “No one can bring down the cavern of Mithras, especially with one strike. Especially not a girl!”

Annabeth hefted her dagger. The ceiling was low. She could reach the capstone easily, but she’d have to make her one strike count.

The doorway behind her was blocked, but in theory, if the room started to collapse, those bricks should weaken and crumble. She should be able to bust her way through before the entire ceiling came down—assuming, of course, that there was something behind the brick wall, not just solid earth; and assuming that Annabeth was quick enough and strong enough and lucky enough. Otherwise, she was about to be a demigod pancake.

“Well, boys,” she said. “Looks like you chose the wrong war god.”

She struck the capstone. The Celestial bronze blade shattered it like a sugar cube. For a moment, nothing happened.

“Ha!” the pater gloated. “You see? Athena has no power here!”

The room shook. A fissure ran across the length of the ceiling and the far end of the cavern collapsed, burying the altar and the pater. More cracks widened. Bricks fell from the arches. Ghosts screamed and ran, but they couldn’t seem to pass through the walls. Apparently they were bound to this chamber even in death.

Annabeth turned. She slammed against the blocked entrance with all her might, and the bricks gave way. As the cavern of Mithras imploded behind her, she lunged into darkness and found herself falling.

ANNABETH THOUGHT SHE KNEW PAIN. She had fallen off the lava wall at Camp Half-Blood. She’d been stabbed in the arm with a poison blade on the Williamsburg Bridge. She had even held the weight of the sky on her shoulders.

But that was nothing compared to landing hard on her ankle.

She immediately knew she’d broken it. Pain like a hot steel wire jabbed its way up her leg and into her hip. The world narrowed to just her, her ankle, and the agony.

She almost blacked out. Her head spun. Her breath became short and rapid.

No, she told herself. You can’t go into shock.

She tried to breathe more slowly. She lay as still as possible until the pain subsided from absolute torture to just horrible throbbing.

Part of her wanted to howl at the world for being so unfair. All this way, just to be stopped by something as common as a broken ankle?

She forced her emotions back down. At camp, she’d been trained to survive in all sorts of bad situations, including injuries like this.

She looked around her. Her dagger had skittered a few feet away. In its dim light she could make out the features of the room. She was lying on a cold floor of sandstone blocks. The ceiling was two stories tall. The doorway through which she’d fallen was ten feet off the ground, now completely blocked with debris that had cascaded into the room, making a rockslide. Scattered around her were old pieces of lumber—some cracked and desiccated, others broken into kindling.

Stupid, she scolded herself. She’d lunged through that doorway, assuming there would be a level corridor or another room. It had never occurred to her that she’d be tumbling into space. The lumber had probably once been a staircase, long ago collapsed.

She inspected her ankle. Her foot didn’t appear too strangely bent. She could feel her toes. She didn’t see any blood. That was all good.

She reached out for a piece of lumber. Even that small bit of movement made her yelp.

The board crumbled in her hand. The wood might be centuries old, or even millennia. She had no way of knowing if this room was older than the shrine of Mithras, or if—like the labyrinth—the rooms were a hodgepodge from many eras thrown randomly together.

“Okay,” she said aloud, just to hear her voice. “Think, Annabeth. Prioritize.”

She remembered a silly wilderness survival course Grover had taught her back at camp. At least it had seemed silly at the time. First step: Scan your surroundings for immediate threats.

This room didn’t seem to be in danger of collapsing. The rockslide had stopped. The walls were solid blocks of stone with no major cracks that she could see. The ceiling was not sagging. Good.

The only exit was on the far wall—an arched doorway that led into darkness. Between her and the doorway, a small brickwork trench cut across the floor, letting water flow through the room from left to right. Maybe plumbing from the Roman days? If the water was drinkable, that was good too.

Piled in one corner were some broken ceramic vases, spilling out shriveled brown clumps that might once have been fruit. Yuck. In another corner were some wooden crates that looked more intact, and some wicker boxes bound with leather straps.

“So, no immediate danger,” she said to herself. “Unless something comes barreling out of that dark tunnel.”

She glared at the doorway, almost daring her luck to get worse. Nothing happened.

“Okay,” she said. “Next step: Take inventory.”

What could she use? She had her water bottle, and more water in that trench if she could reach it. She had her knife. Her backpack was full of colorful string (whee), her laptop, the bronze map, some matches, and some ambrosia for emergencies.

Ah…yeah. This qualified as an emergency. She dug the godly food out of her pack and wolfed it down. As usual, it tasted like comforting memories. This time it was buttered popcorn—movie night with her dad at his place in San Francisco, no stepmom, no stepbrothers, just Annabeth and her father curled up on the sofa watching sappy old romantic comedies.

The ambrosia warmed her whole body. The pain in her leg became a dull throb. Annabeth knew she was still in major trouble. Even ambrosia couldn’t heal broken bones right away. It might speed up the process, but best-case scenario, she wouldn’t be able to put any weight on her foot for a day or more.

She tried to reach her knife, but it was too far away. She scooted in that direction. Pain flared again, like nails were piercing her foot. Her face beaded with sweat, but after one more scoot, she managed to reach the dagger.

She felt better holding it—not just for light and protection, but also because it was so familiar.

What next? Grover’s survival class had mentioned something about staying put and waiting for rescue, but that wasn’t going to happen. Even if Percy somehow managed to trace her steps, the cavern of Mithras had collapsed.

She could try contacting someone with Daedalus’s laptop, but she doubted she could get a signal down here. Besides, who would she call? She couldn’t text anyone who was close enough to help. Demigods never carried cell phones, because their signals attracted too much monstrous attention, and none of her friends would be sitting around checking their e-mail.

An Iris-message? She had water, but she doubted that she could make enough light for a rainbow. The only coin she had was her silver Athenian drachma, which didn’t make a great tribute.

There was another problem with calling for help: this was supposed to be a solo quest. If Annabeth did get rescued, she’d be admitting defeat. Something told her that the Mark of Athena would no longer guide her. She could wander down here forever, and she’d never find the Athena Parthenos.

So…no good staying put and waiting for help. Which meant she had to find a way to keep going on her own.

She opened her water bottle and drank. She hadn’t realized how thirsty she was. When the bottle was empty, she crawled to the gutter and refilled it.

The water was cold and moving swiftly—good signs that it might be safe to drink. She filled her bottle, then cupped some water in her hands and splashed her face. Immediately she felt more alert. She washed off and cleaned her scrapes as best she could.

Annabeth sat up and glared at her ankle.

“You had to break,” she scolded it.

The ankle did not reply.

She’d have to immobilize it in some sort of cast. That was the only way she’d be able to move.

Hmm…

She raised her dagger and inspected the room again in its bronze light. Now that she was closer to the open doorway, she liked it even less. It led into a dark silent corridor. The air wafting out smelled sickly sweet and somehow evil. Unfortunately, Annabeth didn’t see any other way she could go.

With a lot of gasping and blinking back tears, she crawled over to the wreckage of the stairs. She found two planks that were in fairly good shape and long enough for a splint. Then she scooted over to the wicker boxes and used her knife to cut off the leather straps.

While she was psyching herself up to immobilize her ankle, she noticed some faded words on one of the wooden crates: HERMES EXPRESS.

Annabeth scooted excitedly toward the box.

She had no idea what it was doing here, but Hermes delivered all sorts of useful stuff to gods, spirits, and even demigods. Maybe he’d dropped this care package here years ago to help demigods like her with this quest.

She pried it open and pulled out several sheets of Bubble Wrap, but whatever had been inside was gone.

“Hermes!” she protested.

She stared glumly at the Bubble Wrap. Then her mind kicked into gear, and she realized the wrapping was a gift. “Oh…that’s perfect!”

Annabeth covered her broken ankle in a Bubble Wrap cast. She set it with the lumber splints and tied it all together with the leather straps.

Once before, in first aid practice, she’d splinted a fake broken leg for another camper, but she never imagined she’d have to make a splint for herself.

It was hard, painful work, but finally it was done. She searched the wreckage of the stairs until she found part of the railing—a narrow board about four feet long that could serve as a crutch. She put her back against the wall, got her good leg ready, and hauled herself up.

“Whoa.” Black spots danced in her eyes, but she stayed upright.

“Next time,” she muttered to the dark room, “just let me fight a monster. Much easier.”

Above the open doorway, the Mark of Athena blazed to life against the arch.

The fiery owl seemed to be watching her expectantly, as if to say: About time. Oh, you want monsters? Right this way!

Annabeth wondered if that burning mark was based on a real sacred owl. If so, when she survived, she was going to find that owl and punch it in the face.

That thought lifted her spirits. She made it across the trench and hobbled slowly into the corridor.

THE TUNNEL RAN STRAIGHT AND SMOOTH, but after her fall, Annabeth decided to take no chances. She used the wall for support and tapped the floor in front of her with her crutch to make sure there were no traps.

As she walked, the sickly sweet smell got stronger and set her nerves on edge. The sound of running water faded behind her. In its place came a dry chorus of whispers like a million tiny voices. They seemed to be coming from inside the walls, and they were getting louder.

Annabeth tried to speed up, but she couldn’t go much faster without losing her balance or jarring her broken ankle. She hobbled onward, convinced that something was following her. The small voices were massing together, getting closer.

She touched the wall, and her hand came back covered in cobwebs.

She yelped, then cursed herself for making a sound.

It’s only a web, she told herself. But that didn’t stop the roaring in her ears.

She’d expected spiders. She knew what was ahead: The weaver. Her Ladyship. The voice in the dark. But the webs made her realize how close she was.

Her hand trembled as she wiped it on the stones. What had she been thinking? She couldn’t do this quest alone.

Too late, she told herself. Just keep going.

She made her way down the corridor one painful step at a time. The whispering sounds got louder behind her until they sounded like millions of dried leaves swirling in the wind. The cobwebs became thicker, filling the tunnel. Soon she was pushing them out of her face, ripping through gauzy curtains that covered her like Silly String.

Her heart wanted to break out of her chest and run. She stumbled ahead more recklessly, trying to ignore the pain in her ankle.

Finally the corridor ended in a doorway filled waist-high with old lumber. It looked as if someone had tried to barricade the opening. That didn’t bode well, but Annabeth used her crutch to push away the boards as best she could. She crawled over the remaining pile, getting a few dozen splinters in her free hand.

On the other side of the barricade was a chamber the size of a basketball court. The floor was done in Roman mosaics. The remains of tapestries hung from the walls. Two unlit torches sat in wall sconces on either side of the doorway, both covered in cobwebs.

At the far end of the room, the Mark of Athena burned over another doorway. Unfortunately, between Annabeth and that exit, the floor was bisected by a chasm fifty feet across. Spanning the pit were two parallel wooden beams, too far apart for both feet, but each too narrow to walk on unless Annabeth was an acrobat, which she wasn’t, and didn’t have a broken ankle, which she did.

The corridor she’d come from was filled with hissing noises. Cobwebs trembled and danced as the first of the spiders appeared: no larger than gumdrops, but plump and black, skittering over the walls and the floor.

What kind of spiders? Annabeth had no idea. She only knew they were coming for her, and she only had seconds to figure out a plan.

Annabeth wanted to sob. She wanted someone, anyone, to be here for her. She wanted Leo with his fire skills, or Jason with his lightning, or Hazel to collapse the tunnel. Most of all she wanted Percy. She always felt braver when Percy was with her.

I am not going to die here, she told herself. I’m going to see Percy again.

The first spiders were almost to the door. Behind them came the bulk of the army—a black sea of creepy-crawlies.

Annabeth hobbled to one of the wall sconces and snatched up the torch. The end was coated in pitch for easy lighting. Her fingers felt like lead, but she rummaged through her backpack and found the matches. She struck one and set the torch ablaze.

She thrust it into the barricade. The old dry wood caught immediately. Flames leaped to the cobwebs and roared down the corridor in a flash fire, roasting spiders by the thousands.

Annabeth stepped back from her bonfire. She’d bought herself some time, but she doubted that she’d killed all the spiders. They would regroup and swarm again as soon as the fire died.

She stepped to the edge of the chasm.

She shined her light into the pit, but she couldn’t see the bottom. Jumping in would be suicide. She could try to cross one of the bars hand over hand, but she didn’t trust her arm strength, and she didn’t see how she would be able to haul herself up with a full backpack and a broken ankle once she reached the other side.

She crouched and studied the beams. Each had a set of iron eye hooks along the inside, set at one-foot intervals. Maybe the rails had been the sides of a bridge and the middle planks had been removed or destroyed. But eye hooks? Those weren’t for supporting planks. More like…

She glanced at the walls. The same kind of hooks had been used to hang the shredded tapestries.

She realized the beams weren’t meant as a bridge. They were some kind of loom.

Annabeth threw her flaming torch to the other side of the chasm. She had no faith her plan would work, but she pulled all the string out of her backpack and began weaving between the beams, stringing a cat’s cradle pattern back and forth from eye hook to eye hook, doubling and tripling the line.

Her hands moved with blazing speed. She stopped thinking about the task and just did it, looping and tying off lines, slowly extending her woven net over the pit.

She forgot the pain in her leg and the fiery barricade guttering out behind her. She inched over the chasm. The weaving held her weight. Before she knew it, she was halfway across.

How had she learned to do this?

It’s Athena, she told herself. My mother’s skill with useful crafts. Weaving had never seemed particularly useful to Annabeth—until now.

She glanced behind her. The barricade fire was dying. A few spiders crawled in around the edges of the doorway.

Desperately she continued weaving, and finally she made it across. She snatched up the torch and thrust it into her woven bridge. Flames raced along the string. Even the beams caught fire as if they’d been pre-soaked in oil.

For a moment, the bridge burned in a clear pattern—a fiery row of identical owls. Had Annabeth really woven them into the string, or was it some kind of magic? She didn’t know, but as the spiders began to cross, the beams crumbled and collapsed into the pit.

Annabeth held her breath. She didn’t see any reason why the spiders couldn’t reach her by climbing the walls or the ceiling. If they started to do that, she’d have to run for it, and she was pretty sure she couldn’t move fast enough.

For some reason, the spiders didn’t follow. They massed at the edge of the pit—a seething black carpet of creepiness. Then they dispersed, flooding back into the burned corridor, almost as if Annabeth was no longer interesting.

“Or I passed a test,” she said aloud.

Her torch sputtered out, leaving her with only the light of her dagger. She realized that she’d left her makeshift crutch on the other side of the chasm.

She felt exhausted and out of tricks, but her mind was clear. Her panic seemed to have burned up along with that woven bridge.

The weaver, she thought. I must be close. At least I know what’s ahead.

She made her way down the next corridor, hopping to keep the weight off her bad foot.

She didn’t have far to go.

After twenty feet, the tunnel opened into a cavern as large as a cathedral, so majestic that Annabeth had trouble processing everything she saw. She guessed that this was the room from Percy’s dream, but it wasn’t dark. Bronze braziers of magical light, like the gods used on Mount Olympus, glowed around the circumference of the room, interspersed with gorgeous tapestries. The stone floor was webbed with fissures like a sheet of ice. The ceiling was so high, it was lost in the gloom and layers upon layers of spiderwebs.

Strands of silk as thick as pillars ran from the ceiling all over the room, anchoring the walls and the floor like the cables of a suspension bridge.

Webs also surrounded the centerpiece of the shrine, which was so intimidating that Annabeth had trouble raising her eyes to look at it. Looming over her was a forty-foot-tall statue of Athena, with luminous ivory skin and a dress of gold. In her outstretched hand, Athena held a statue of Nike, the winged victory goddess—a statue that looked tiny from here, but was probably as tall as a real person. Athena’s other hand rested on a shield as big as a billboard, with a sculpted snake peeking out from behind, as if Athena was protecting it.

The goddess’s face was serene and kindly…and it looked like Athena. Annabeth had seen many statues that didn’t resemble her mom at all, but this giant version, made thousands of years ago, made her think that the artist must have met Athena in person. He had captured her perfectly.

“Athena Parthenos,” Annabeth murmured. “It’s really here.”

All her life, she had wanted to visit the Parthenon. Now she was seeing the main attraction that used to be there—and she was the first child of Athena to do so in millennia.

She realized her mouth was hanging open. She forced herself to swallow. Annabeth could have stood there all day looking at the statue, but she had only accomplished half her mission. She had found the Athena Parthenos. Now, how could she rescue it from this cavern?

Strands of web covered it like a gauze pavilion. Annabeth suspected that without those webs, the statue would have fallen through the weakened floor long ago. As she stepped into the room, she could see that the cracks below were so wide, she could have lost her foot in them. Beneath the cracks, she saw nothing but empty darkness.

A chill washed over her. Where was the guardian? How could Annabeth free the statue without collapsing the floor? She couldn’t very well shove the Athena Parthenos down the corridor that she’d come from.

She scanned the chamber, hoping to see something that might help. Her eyes wandered over the tapestries, which were heart-wrenchingly beautiful. One showed a pastoral scene so three-dimensional, it could’ve been a window. Another tapestry showed the gods battling the giants. Annabeth saw a landscape of the Underworld. Next to it was the skyline of modern Rome. And in the tapestry to her left…

She caught her breath. It was a portrait of two demigods kissing underwater: Annabeth and Percy, the day their friends had thrown them into the canoe lake at camp. It was so lifelike that she wondered if the weaver had been there, lurking in the lake with a waterproof camera.

“How is that possible?” she murmured.

Above her in the gloom, a voice spoke. “For ages I have known that you would come, my sweet.”

Annabeth shuddered. Suddenly she was seven years old again, hiding under her covers, waiting for the spiders to attack her in the night. The voice sounded just as Percy had described: an angry buzz in multiple tones, female but not human.

In the webs above the statue, something moved—something dark and large.

“I have seen you in my dreams,” the voice said, sickly sweet and evil, like the smell in the corridors. “I had to make sure you were worthy, the only child of Athena clever enough to pass my tests and reach this place alive. Indeed, you are her most talented child. This will make your death so much more painful to my old enemy when you fail utterly.”

The pain in Annabeth’s ankle was nothing compared to the icy acid now filling her veins. She wanted to run. She wanted to plead for mercy. But she couldn’t show weakness—not now.

“You’re Arachne,” she called out. “The weaver who was turned into a spider.”

The figure descended, becoming clearer and more horrible. “Cursed by your mother,” she said. “Scorned by all and made into a hideous thing…because I was the better weaver.”

“But you lost the contest,” Annabeth said.

“That’s the story written by the winner!” cried Arachne. “Look on my work! See for yourself!”

Annabeth didn’t have to. The tapestries were the best she’d ever seen—better than the witch Circe’s work, and, yes, even better than some weavings she’d seen on Mount Olympus. She wondered if her mother truly had lost—if she’d hidden Arachne away and rewritten the truth. But right now, it didn’t matter.

“You’ve been guarding this statue since the ancient times,” Annabeth guessed. “But it doesn’t belong here. I’m taking it back.”

“Ha,” Arachne said.

Even Annabeth had to admit her threat sounded ridiculous. How could one girl in a Bubble Wrap ankle cast remove this huge statue from its underground chamber?

“I’m afraid you would have to defeat me first, my sweet,” Arachne said. “And alas, that is impossible.”

The creature appeared from the curtains of webbing, and Annabeth realized that her quest was hopeless. She was about to die.

Arachne had the body of a giant black widow, with a hairy red hourglass mark on the underside of her abdomen and a pair of oozing spinnerets. Her eight spindly legs were lined with curved barbs as big as Annabeth’s dagger. If the spider came any closer, her sweet stench alone would have been enough to make Annabeth faint. But the most horrible part was her misshapen face.

She might once have been a beautiful woman. Now black mandibles protruded from her mouth like tusks. Her other teeth had grown into thin white needles. Fine dark whiskers dotted her cheeks. Her eyes were large, lidless, and pure black, with two smaller eyes sticking out of her temples.

The creature made a violent rip-rip-rip sound that might have been laughter.

“Now I will feast on you, my sweet,” Arachne said. “But do not fear. I will make a beautiful tapestry depicting your death.”

LEO WISHED HE WASN’T SO GOOD.

Really, sometimes it was just embarrassing. If he hadn’t had such an eye for mechanical stuff, they might never have found the secret chute, gotten lost in the underground, and been attacked by metal dudes. But he just couldn’t help himself.

Part of it was Hazel’s fault. For a girl with super underground senses, she wasn’t much good in Rome. She kept leading them around and around the city, getting dizzy, and doubling back.

“Sorry,” she said. “It’s just…there’s so much underground here, so many layers, it’s overwhelming. Like standing in the middle of an orchestra and trying to concentrate on a single instrument. I’m going deaf.”

As a result, they got a tour of Rome. Frank seemed happy to plod along like a big sheepdog (hmm, Leo wondered if he could turn into one of those, or even better: a horse that Leo could ride). But Leo started to get impatient. His feet were sore, the day was sunny and hot, and the streets were choked with tourists.

The Forum was okay, but it was mostly ruins overgrown with bushes and trees. It took a lot of imagination to see it as the bustling center of Ancient Rome. Leo could only manage it because he’d seen New Rome in California.

They passed big churches, freestanding arches, clothing stores, and fast-food restaurants. One statue of some Ancient Roman dude seemed to be pointing to a nearby McDonald’s.

On the wider streets, the car traffic was absolutely nuts—man, Leo thought people in Houston drove crazy—but they spent most of their time weaving through small alleys, coming across fountains and little cafés where Leo was not allowed to rest.

“I never thought I’d get to see Rome,” Hazel said. “When I was alive, I mean the first time, Mussolini was in charge. We were at war.”

“Mussolini?” Leo frowned. “Wasn’t he like BFFs with Hitler?”

Hazel stared at him like he was an alien. “BFFs?”

“Never mind.”

“I’d love to see the Trevi Fountain,” she said.

“There’s a fountain on every block,” Leo grumbled.

“Or the Spanish Steps,” Hazel said.

“Why would you come to Italy to see Spanish steps?” Leo asked. “That’s like going to China for Mexican food, isn’t it?”

“You’re hopeless,” Hazel complained.

“So I’ve been told.”

She turned to Frank and grabbed his hand, as if Leo had ceased to exist. “Come on. I think we should go this way.”

Frank gave Leo a confused smile—like he couldn’t decide whether to gloat or to thank Leo for being a doofus—but he cheerfully let Hazel drag him along.

After walking forever, Hazel stopped in front of a church. At least, Leo assumed it was a church. The main section had a big domed roof. The entrance had a triangular roof, typical Roman columns, and an inscription across the top: M. AGRIPPA something or other.

“Latin for Get a grip?” Leo speculated.

“This is our best bet.” Hazel sounded more certain than she had all day. “There should be a secret passage somewhere inside.”

Tour groups milled around the steps. Guides held up colored placards with different numbers and lectured in dozens of languages like they were playing some kind of international bingo.

Leo listened to the Spanish tour guide for a few seconds, and then he reported to his friends, “This is the Pantheon. It was originally built by Marcus Agrippa as a temple to the gods. After it burned down, Emperor Hadrian rebuilt it, and it’s been standing for two thousand years. It’s one of the best-preserved Roman buildings in the world.”

Frank and Hazel stared at him.

“How did you know that?” Hazel asked.

“I’m naturally brilliant.”

“Centaur poop,” Frank said. “He eavesdropped on a tour group.”

Leo grinned. “Maybe. Come on. Let’s go find that secret passage. I hope this place has air conditioning.”

Of course, no AC.

On the bright side, there were no lines and no admission fee, so they just muscled their way past the tour groups and walked on in.

The interior was pretty impressive, considering it had been constructed two thousand years ago. The marble floor was patterned with squares and circles like a Roman tic-tac-toe game. The main space was one huge chamber with a circular rotunda, sort of like a capitol building back in the States. Lining the walls were different shrines and statues and tombs and stuff. But the real eye-catcher was the dome overhead. All the light in the building came from one circular opening right at the top. A beam of sunlight slanted into the rotunda and glowed on the floor, like Zeus was up there with a magnifying glass, trying to fry puny humans.

Leo was no architect like Annabeth, but he could appreciate the engineering. The Romans had made the dome out of big stone panels, but they’d hollowed out each panel in a square-within-square pattern. It looked cool. Leo figured it also made the dome lighter and easier to support.

He didn’t mention that to his friends. He doubted they would care, but if Annabeth were here, she would’ve spent the whole day talking about it. Thinking about that made Leo wonder how she was doing on her Mark of Athena expedition. Leo never thought he’d feel this way, but he was worried about that scary blond girl.

Hazel stopped in the middle of the room and turned in a circle. “This is amazing. In the old days, the children of Vulcan would come here in secret to consecrate demigod weapons. This is where Imperial gold was enchanted.”

Leo wondered how that worked. He imagined a bunch of demigods in dark robes trying to quietly roll a scorpion ballista through the front doors.

“But we’re not here because of that,” he guessed.

“No,” Hazel said. “There’s an entrance—a tunnel that will lead us toward Nico. I can sense it close by. I’m not sure where.”

Frank grunted. “If this building is two thousand years old, it makes sense there could be some kind of secret passage left over from the Roman days.”

That’s when Leo made his mistake of simply being too good.

He scanned the temple’s interior, thinking: If I were designing a secret passage, where would I put it?

He could sometimes figure out how a machine worked by putting his hand on it. He’d learned to fly a helicopter that way. He’d fixed Festus the dragon that way (before Festus crashed and burned). Once he’d even reprogrammed the electronic billboards in Times Square to read: ALL DA LADIES LUV LEO…accidentally, of course.

Now he tried to sense the workings of this ancient building. He turned toward a red marble altar-looking thing with a statue of the Virgin Mary on the top. “Over there,” he said.

He marched confidently to the shrine. It was shaped sort of like a fireplace, with an arched recess at the bottom. The mantel was inscribed with a name, like a tomb.

“The passage is around here,” he said. “This guy’s final resting place is in the way. Raphael somebody?”

“Famous painter, I think,” Hazel said.

Leo shrugged. He had a cousin named Raphael, and he didn’t think much of the name. He wondered if he could produce a stick of dynamite from his tool belt and do a little discreet demolition; but he figured the caretakers of this place probably wouldn’t approve.

“Hold on…” Leo looked around to make sure they weren’t being watched.

Most of the tour groups were gawking at the dome, but one trio made Leo uneasy. About fifty feet away, some overweight middle-aged dudes with American accents were conversing loudly, complaining to each other about the heat. They looked like manatees stuffed into beach clothes—sandals, walking shorts, touristy T-shirts and floppy hats. Their legs were big and pasty and covered with spider veins. The guys acted extremely bored, and Leo wondered why they were hanging around.

They weren’t watching him. Leo wasn’t sure why they made him nervous. Maybe he just didn’t like manatees.

Forget them, Leo told himself.

He slipped around the side of the tomb. He ran his hand down the back of a Roman column, all the way to the base. Right at the bottom, a series of lines had been etched into the marble—Roman numerals.

“Heh,” Leo said. “Not very elegant, but effective.”

“What is?” Frank asked.

“The combination for a lock.” He felt around the back of the column some more and discovered a square hole about the size of an electrical socket. “The lock face itself has been ripped out—probably vandalized sometime in the last few centuries. But I should be able to control the mechanism inside, if I can…”

Leo placed his hand on the marble floor. He could sense old bronze gears under the surface of the stone. Regular bronze would have corroded and become unusable long ago, but these were Celestial bronze—the handiwork of a demigod. With a little willpower, Leo urged them to move, using the Roman numerals to guide him. The cylinders turned—click, click, click. Then click, click.

On the floor next to the wall, one section of marble tile slid under another, revealing a dark square opening barely large enough to wiggle through.

“Romans must’ve been small.” Leo looked at Frank appraisingly. “You’ll need to change into something thinner to get through here.”

“That’s not nice!” Hazel chided.

“What? Just saying—”

“Don’t worry about it,” Frank mumbled. “We should go get the others before we explore. That’s what Piper said.”

“They’re halfway across the city,” Leo reminded him. “Besides, uh, I’m not sure I can close this hatch again. The gears are pretty old.”

“Great,” Frank said. “How do we know it’s safe down there?”

Hazel knelt. She put her hand over the opening as if checking the temperature. “There’s nothing alive…at least not for several hundred feet. The tunnel slants down, then levels out and goes south, more or less. I don’t sense any traps…”

“How can you tell all that?” Leo asked.

She shrugged. “Same way you can pick locks on marble columns, I guess. I’m glad you’re not into robbing banks.”

“Oh…bank vaults,” Leo said. “Never thought about that.”

“Forget I said anything.” Hazel sighed. “Look, it’s not three o’clock yet. We can at least do a little exploring, try to pinpoint Nico’s location before we contact the others. You two stay here until I call for you. I want to check things out, make sure the tunnel is structurally sound. I’ll be able to tell more once I’m underground.”

Frank scowled. “We can’t let you go by yourself. You could get hurt.”

“Frank, I can take care of myself,” she said. “Underground is my specialty. It’s safest for all of us if I go first.”

“Unless Frank wants to turn into a mole,” Leo suggested. “Or a prairie dog. Those things are awesome.”

“Shut up,” Frank mumbled.

“Or a badger.”

Frank jabbed a finger at Leo’s face. “Valdez, I swear—”

“Both of you, be quiet,” Hazel scolded. “I’ll be back soon. Give me ten minutes. If you don’t hear from me by then…Never mind. I’ll be fine. Just try not to kill each other while I’m down there.”

She dropped down the hole. Leo and Frank blocked her from view as best they could. They stood shoulder to shoulder, trying to look casual, like it was completely natural for two teenaged guys to hang around Raphael’s tomb.

Tour groups came and went. Most ignored Leo and Frank. A few people glanced at them apprehensively and kept walking. Maybe the tourists thought they would ask for tips. For some reason, Leo could unnerve people when he grinned.

The three American manatees were still hanging out in the middle of the room. One of them wore a T-shirt that said ROMA, as if he’d forget what city he was in if he didn’t wear it. Every once in a while, he would glance over at Leo and Frank like he found their presence distasteful.

Something about that dude bothered Leo. He wished Hazel would hurry up.

“She talked to me earlier,” Frank said abruptly. “Hazel told me you figured out about my lifeline.”

Leo stirred. He’d almost forgotten Frank was standing next to him.

“Your lifeline…oh, the burning stick. Right.” Leo resisted the urge to set his hand ablaze and yell: Bwah ha ha! The idea was sort of funny, but he wasn’t that cruel.

“Look, man,” he said. “It’s cool. I’d never do anything to put you in danger. We’re on the same team.”

Frank fiddled with his centurion badge. “I always knew fire could kill me, but since my grandmother’s mansion burned down in Vancouver…it seems a lot more real.”

Leo nodded. He felt sympathy for Frank, but the guy didn’t make it easy when he talked about his family mansion. Sort of like saying, I crashed my Lamborghini, and waiting for people to say, Oh, you poor baby!

Of course Leo didn’t tell him that. “Your grandmother—did she die in that fire? You didn’t say.”

“I—I don’t know. She was sick, and pretty old. She said she would die in her own time, in her own way. But I think she made it out of the fire. I saw this bird flying up from the flames.”

Leo thought about that. “So your whole family has the shape-changing thing?”

“I guess,” Frank said. “My mom did. Grandmother thought that’s what got her killed in Afghanistan, in the war. Mom tried to help some of her buddies, and…I don’t know exactly what happened. There was a firebomb.”

Leo winced with sympathy. “So we both lost our moms to fire.”

He hadn’t been planning on it, but he told Frank the whole story of the night at the workshop when Gaea had appeared to him, and his mother had died.

Frank’s eyes got watery. “I never like it when people tell me, Sorry about your mom.”

“It never feels genuine,” Leo agreed.

“But I’m sorry about your mom.”

“Thanks.”

No sign of Hazel. The American tourists were still milling around the Pantheon. They seemed to be circling closer, like they were trying to sneak up on Raphael’s tomb without it noticing.

“Back at Camp Jupiter,” Frank said, “our cabin Lar, Reticulus, told me I have more power than most demigods, being a son of Mars, plus having the shape-changing ability from my mom’s side. He said that’s why my life is tied to a burning stick. It’s such a huge weakness that it kind of balances things out.”

Leo remembered his conversation with Nemesis the revenge goddess at the Great Salt Lake. She’d said something similar about wanting the scales to balance. Good luck is a sham. True success requires sacrifice.

Her fortune cookie was still in Leo’s tool belt, waiting to be opened. Soon you will face a problem you cannot solve, though I could help you…for a price.

Leo wished he could pluck that memory out of his head and shove it in his tool belt. It was taking up too much space. “We’ve all got weaknesses,” he said. “Me, for instance. I’m tragically funny and good-looking.”

Frank snorted. “You might have weaknesses. But your life doesn’t depend on a piece of firewood.”

“No,” Leo admitted. He started thinking: if Frank’s problem were his problem, how would he solve it? Almost every design flaw could be fixed. “I wonder…”

He looked across the room and faltered. The three American tourists were coming their way; no more circling or sneaking. They were making a straight line for Raphael’s tomb, and all three were glaring at Leo.

“Uh, Frank?” Leo asked. “Has it been ten minutes yet?”

Frank followed his gaze. The Americans’ faces were angry and confused, like they were sleepwalking through a very annoying nightmare.

“Leo Valdez,” called the guy in the ROMA shirt. His voice had changed. It was hollow and metallic. He spoke English as if it was a second language. “We meet again.”

All three tourists blinked, and their eyes turned solid gold.

Frank yelped. “Eidolons!”

The manatees clenched their beefy fists. Normally, Leo wouldn’t have worried about getting murdered by overweight guys in floppy hats, but he suspected the eidolons were dangerous even in those bodies, especially since the spirits wouldn’t care whether their hosts survived or not.

“They can’t fit down the hole,” Leo said.

“Right,” Frank said. “Underground is sounding really good.”

He turned into a snake and slithered over the edge. Leo jumped in after him while the spirits began to wail above, “Valdez! Kill Valdez!”

ONE PROBLEM SOLVED: the hatch above them closed automatically, cutting off their pursuers. It also cut off all light, but Leo and Frank could deal with that. Leo just hoped they didn’t need to get out the same way they came in. He wasn’t sure he could open the tile from underneath.

At least the possessed manatee dudes were on the other side. Over Leo’s head, the marble floor shuddered, like fat touristy feet were kicking it.

Frank must have turned back to human form. Leo could hear him wheezing in the dark.

“What now?” Frank asked.

“Okay, don’t freak,” Leo said. “I’m going to summon a little fire, just so we can see.”

“Thanks for the warning.”

Leo’s index finger blazed like a birthday candle. In front of them stretched a stone tunnel with a low ceiling. Just as Hazel had predicted, it slanted down, then leveled out and went south.

“Well,” Leo said. “It only goes in one direction.”

“Let’s find Hazel,” Frank said.

Leo had no argument with that suggestion. They made their way down the corridor, Leo going first with the fire. He was glad to have Frank at his back, big and strong and able to turn into scary animals in case those possessed tourists somehow broke through the hatch, squeezed inside, and followed them. He wondered if the eidolons might just leave those bodies behind, seep underground, and possess one of them instead.

Oh, there’s my happy thought for the day! Leo scolded himself.

After a hundred feet or so, they turned a corner and found Hazel. In the light of her golden cavalry sword, she was examining a door. She was so engrossed, she didn’t notice them until Leo said, “Hi.”

Hazel whirled, trying to swing her spatha. Fortunately for Leo’s face, the blade was too long to wield in the corridor.

“What are you doing here?” Hazel demanded.

Leo gulped. “Sorry. We ran into some angry tourists.” He told her what had happened.

She hissed in frustration. “I hate eidolons. I thought Piper made them promise to stay away.”

“Oh…” Frank said, like he’d just had his own daily happy thought. “Piper made them promise to stay off the ship and not possess any of us. But if they followed us, and used other bodies to attack us, then they’re not technically breaking their vow.…”

“Great,” Leo muttered. “Eidolons who are also lawyers. Now I really want to kill them.”

“Okay, forget them for now,” Hazel said. “This door is giving me fits. Leo, can you try your skill with the lock?”

Leo cracked his knuckles. “Stand aside for the master, please.”

The door was interesting, much more complicated than the Roman numeral combination lock above. The entire door was coated in Imperial gold. A mechanical sphere about the size of a bowling ball was embedded in the center. The sphere was constructed from five concentric rings, each inscribed with zodiac symbols—the bull, the scorpion, et cetera—and seemingly random numbers and letters.

“These letters are Greek,” Leo said in surprise.

“Well, lots of Romans spoke Greek,” Hazel said.

“I guess,” Leo said. “But this workmanship…no offense to you Camp Jupiter types, but this is too complicated to be Roman.”

Frank snorted. “Whereas you Greeks just love making things complicated.”

“Hey,” Leo protested. “All I’m saying is this machinery is delicate, sophisticated. It reminds me of…” Leo stared at the sphere, trying to recall where he’d read or heard about a similar ancient machine. “It’s a more advanced sort of lock,” he decided. “You line up the symbols on the different rings in the right order, and that opens the door.”

“But what’s the right order?” Hazel asked.

“Good question. Greek spheres…astronomy, geometry…” Leo got a warm feeling inside. “Oh, no way. I wonder…What’s the value of pi?”

Frank frowned. “What kind of pie?”

“He means the number,” Hazel guessed. “I learned that in math class once, but—”

“It’s used to measure circles,” Leo said. “This sphere, if it’s made by the guy I’m thinking of…”

Hazel and Frank both stared at him blankly.

“Never mind,” Leo said. “I’m pretty sure pi is, uh, 3.1415 blah blah blah. The number goes on forever, but the sphere has only five rings, so that should be enough, if I’m right.”

“And if you’re not?” Frank asked.

“Well, then, Leo fall down, go boom. Let’s find out!”

He turned the rings, starting on the outside and moving in. He ignored the zodiac signs and letters, lining up the correct numbers so they made the value of pi. Nothing happened.

“I’m stupid,” Leo mumbled. “Pi would expand outward, because it’s infinite.”

He reversed the order of the numbers, starting in the center and working toward the edge. When he aligned the last ring, something inside the sphere clicked. The door swung open.

Leo beamed at his friends. “That, good people, is how we do things in Leo World. Come on in!”

“I hate Leo World,” Frank muttered.

Hazel laughed.

Inside was enough cool stuff to keep Leo busy for years. The room was about the size of the forge back at Camp Half-Blood, with bronze-topped worktables along the walls, and baskets full of ancient metalworking tools. Dozens of bronze and gold spheres like steampunk basketballs sat around in various stages of disassembly. Loose gears and wiring littered the floor. Thick metal cables ran from each table toward the back of the room, where there was an enclosed loft like a theater’s sound booth. Stairs led up to the booth on either side. All the cables seemed to run into it. Next to the stairs on the left, a row of cubbyholes was filled with leather cylinders—probably ancient scroll cases.

Leo was about to head toward the tables when he glanced to his left and nearly jumped out of his shoes. Flanking the doorway were two armored manikins—like skeletal scarecrows made from bronze pipes, outfitted with full suits of Roman armor, shield and sword.

“Dude.” Leo walked up to one. “These would be awesome if they worked.”

Frank edged away from the manikins. “Those things are going to come alive and attack us, aren’t they?”

Leo laughed. “Not a chance. They aren’t complete.” He tapped the nearest manikin’s neck, where loose copper wires sprouted from underneath its breastplate. “Look, the head’s wiring has been disconnected. And here, at the elbow, the pulley system for this joint is out of alignment. My guess? The Romans were trying to duplicate a Greek design, but they didn’t have the skill.”

Hazel arched her eyebrows. “The Romans weren’t good enough at being complicated, I suppose.”

“Or delicate,” Frank added. “Or sophisticated.”

“Hey, I just call it like I see it.” Leo jiggled the manikin’s head, making it nod like it was agreeing with him. “Still…a pretty impressive try. I’ve heard legends that the Romans confiscated the writings of Archimedes, but—”

“Archimedes?” Hazel looked baffled. “Wasn’t he an ancient mathematician or something?”

Leo laughed. “He was a lot more than that. He was only the most famous son of Hephaestus who ever lived.”

Frank scratched his ear. “I’ve heard his name before, but how can you be sure this manikin is his design?”

“It has to be!” Leo said. “Look, I’ve read all about Archimedes. He’s a hero to Cabin Nine. The dude was Greek, right? He lived in one of the Greek colonies in southern Italy, back before Rome got all huge and took over. Finally the Romans moved in and destroyed his city. The Roman general wanted to spare Archimedes, because he was so valuable—sort of like the Einstein of the ancient world—but some stupid Roman soldier killed him.”

“There you go again,” Hazel muttered. “Stupid and Roman don’t always go together, Leo.”

Frank grunted agreement. “How do you know all this, anyway?” he demanded. “Is there a Spanish tour guide around here?”

“No, man,” Leo said. “You can’t be a demigod who’s into building stuff and not know about Archimedes. The guy was seriously elite. He calculated the value of pi. He did all this math stuff we still use for engineering. He invented a hydraulic screw that could move water through pipes.”

Hazel scowled. “A hydraulic screw. Excuse me for not knowing about that awesome achievement.”

“He also built a death ray made of mirrors that could burn enemy ships,” Leo said. “Is that awesome enough for you?”

“I saw something about that on TV,” Frank admitted. “They proved it didn’t work.”

“Ah, that’s just because modern mortals don’t know how to use Celestial bronze,” Leo said. “That’s the key. Archimedes also invented a massive claw that could swing on a crane and pluck enemy ships out of the water.”

“Okay, that’s cool,” Frank admitted. “I love grabber-arm games.”

“Well, there you go,” Leo said. “Anyway, all his inventions weren’t enough. The Romans destroyed his city. Archimedes was killed. According to legends, the Roman general was a big fan of his work, so he raided Archimedes’s workshop and carted a bunch of souvenirs back to Rome. They disappeared from history, except…” Leo waved his hands at the stuff on the tables. “Here they are.”

“Metal basketballs?” Hazel asked.

Leo couldn’t believe that they didn’t appreciate what they were looking at, but he tried to contain his irritation. “Guys, Archimedes constructed spheres. The Romans couldn’t figure them out. They thought they were just for telling time or following constellations, because they were covered with pictures of stars and planets. But that’s like finding a rifle and thinking it’s a walking stick.”

“Leo, the Romans were top-notch engineers,” Hazel reminded him. “They built aqueducts, roads—”

“Siege weapons,” Frank added. “Public sanitation.”

“Yeah, fine,” Leo said. “But Archimedes was in a class by himself. His spheres could do all sorts of things, only nobody is sure…”

Suddenly Leo got an idea so incredible that his nose burst into flames. He patted it out as quickly as possible. Man, it was embarrassing when that happened.

He ran to the row of cubbyholes and examined the markings on the scroll cases. “Oh, gods. This is it!”

He gingerly lifted out one of the scrolls. He wasn’t great at Ancient Greek, but he could tell the inscription on the case read On Building Spheres.

“Guys, this is the lost book!” His hands were shaking. “Archimedes wrote this, describing his construction methods, but all the copies were lost in ancient times. If I can translate this…”

The possibilities were endless. For Leo, the quest had now totally taken on a new dimension. Leo had to get the spheres and scrolls safely out of here. He had to protect this stuff until he could get it back to Bunker 9 and study it.

“The secrets of Archimedes,” he murmured. “Guys, this is bigger than Daedalus’s laptop. If there’s a Roman attack on Camp Half-Blood, these secrets could save the camp. They might even give us an edge over Gaea and the giants!”

Hazel and Frank glanced at each other skeptically.

“Okay,” Hazel said. “We didn’t come here for a scroll, but I guess we can take it with us.”

“Assuming,” Frank added, “that you don’t mind sharing its secrets with us stupid uncomplicated Romans.”

“What?” Leo stared at him blankly. “No. Look, I didn’t mean to insult— Ah, never mind. The point is this is good news!”

For the first time in days, Leo felt really hopeful.

Naturally, that’s when everything went wrong.

On the table next to Hazel and Frank, one of the orbs clicked and whirred. A row of spindly legs extended from its equator. The orb stood, and two bronze cables shot out of the top, hitting Hazel and Frank like Taser wires. Leo’s friends both crumpled to the floor.

Leo lunged to help them, but the two armored manikins that couldn’t possibly move did move. They drew their swords and stepped toward Leo.

The one on the left turned its crooked helmet, which was shaped like a wolf’s head. Despite the fact that it had no face or mouth, a familiar hollow voice spoke from behind its visor.

“You cannot escape us, Leo Valdez,” it said. “We do not like possessing machines, but they are better than tourists. You will not leave here alive.”

LEO AGREED WITH NEMESIS ABOUT ONE THING: good luck was a sham. At least when it came to Leo’s luck.

Last winter he had watched in horror while a family of Cyclopes prepared to roast Jason and Piper with hot sauce. He’d schemed his way out of that one and saved his friends all by himself, but at least he’d had time to think.

Now, not so much. Hazel and Frank had been knocked out by the tendrils of a possessed steampunk bowling ball. Two suits of armor with bad attitudes were about to kill him.

Leo couldn’t blast them with fire. Suits of armor wouldn’t be hurt by that. Besides, Hazel and Frank were too close. He didn’t want to burn them, or accidentally hit the piece of firewood that controlled Frank’s life.

On Leo’s right, the suit of armor with a lion’s head helmet creaked its wiry neck and regarded Hazel and Frank, who were still lying unconscious.

“A male and female demigod,” said Lion Head. “These will do, if the others die.” Its hollow face mask turned back to Leo. “We do not need you, Leo Valdez.”

“Oh, hey!” Leo tried for a winning smile. “You always need Leo Valdez!”

He spread his hands and hoped he looked confident and useful, not desperate and terrified. He wondered if it was too late to write TEAM LEO on his shirt.

Sadly, the suits of armor were not as easily swayed as the Narcissus Fan Club had been.

The one with the wolf-headed helmet snarled, “I have been in your mind, Leo. I helped you start the war.”

Leo’s smile crumbled. He took a step back. “That was you?”

Now he understood why those tourists had bothered him right away, and why this thing’s voice sounded so familiar. He’d heard it in his mind.

“You made me fire the ballista?” Leo demanded. “You call that helping?”

“I know how you think,” said Wolf Head. “I know your limits. You are small and alone. You need friends to protect you. Without them, you are unable to withstand me. I vowed not to possess you again, but I can still kill you.”

The armored dudes stepped forward. The points of their swords hovered a few inches from Leo’s face.

Leo’s fear suddenly made way for a whole lot of anger. This eidolon in the wolf helmet had shamed him, controlled him, and made him attack New Rome. It had endangered his friends and botched their quest.

Leo glanced at the dormant spheres on the worktables. He considered his tool belt. He thought about the loft behind him—the area that looked like a sound booth. Presto: Operation Junk Pile was born.

“First: you don’t know me,” he told Wolf Head. “And second: Bye.”

He lunged for the stairs and bounded to the top. The suits of armor were scary, but they were not fast. As Leo suspected, the loft had doors on either side—folding metal gates. The operators would’ve wanted protection in case their creations went haywire…like now. Leo slammed both gates shut and summoned fire to his hands, fusing the locks.

The suits of armor closed in on either side. They rattled the gates, hacking at them with their swords.

“This is foolish,” said Lion Head. “You only delay your death.”

“Delaying death is one of my favorite hobbies.” Leo scanned his new home. Overlooking the workshop was a single table like a control board. It was crowded with junk, but most of it Leo dismissed immediately: a diagram for a human catapult that would never work; a strange black sword (Leo was no good with swords); a large bronze mirror (Leo’s reflection looked terrible); and a set of tools that someone had broken, either in frustration or clumsiness.

He focused on the main project. In the center of the table, someone had disassembled an Archimedes sphere. Gears, springs, levers, and rods were littered around it. All the bronze cables to the room below were connected to a metal plate under the sphere. Leo could sense the Celestial bronze running through the workshop like arteries from a heart—ready to conduct magical energy from this spot.

“One basketball to rule them all,” Leo muttered.

This sphere was a master regulator. He was standing at Ancient Roman mission control.

“Leo Valdez!” the spirit howled. “Open this gate or I will kill you!”

“A fair and generous offer!” Leo said, his eyes still on the sphere. “Just let me finish this. A last request, all right?”

That must have confused the spirits, because they momentarily stopped hacking at the bars.

Leo’s hands flew over the sphere, reassembling its missing pieces. Why did the stupid Romans have to take apart such a beautiful machine? They had killed Archimedes, stolen his stuff, then messed with a piece of equipment they could never understand. On the other hand, at least they’d had the sense to lock it away for two thousand years so that Leo could retrieve it.

The eidolons started pounding on the gates again.

“Who is it?” Leo called.

“Valdez!” Wolf Head bellowed.

“Valdez who?” Leo asked.

Eventually the eidolons would realize they couldn’t get in. Then, if Wolf Head truly knew Leo’s mind, he would decide there were other ways to force his cooperation. Leo had to work faster.

He connected the gears, got one wrong, and had to start again. Hephaestus’s Hand Grenades, this was hard!

Finally he got the last spring in place. The ham-fisted Romans had almost ruined the tension adjuster, but Leo pulled a set of watchmaker’s tools from his belt and did some final calibrations. Archimedes was a genius—assuming this thing actually worked.

He wound the starter coil. The gears began to turn. Leo closed the top of the sphere and studied its concentric circles—similar to the ones on the workshop door.

“Valdez!” Wolf Head pounded on the gate. “Our third comrade will kill your friends!”

Leo cursed under his breath. Our third comrade. He glanced down at the spindly-legged Taser ball that had knocked out Hazel and Frank. He had figured eidolon number three was hiding inside that thing. But Leo still had to deduce the right sequence to activate this control sphere.

“Yeah, okay,” he called. “You got me. Just…just a sec.”

“No more seconds!” Wolf Head shouted. “Open this gate now, or they die.”

The possessed Taser ball lashed out with its tendrils and sent another shock through Hazel and Frank. Their unconscious bodies flinched. That kind of electricity might have stopped their hearts.

Leo held back tears. This was too hard. He couldn’t do it.

He stared at the face of the sphere—seven rings, each one covered with tiny Greek letters, numbers, and zodiac signs. The answer wouldn’t be pi. Archimedes would never do the same thing twice. Besides, just by putting his hand on the sphere Leo could feel that the sequence had been generated randomly. It was something only Archimedes would know.

Supposedly, Archimedes’s last words had been: Don’t disturb my circles.

No one knew what that meant, but Leo could apply it to this sphere. The lock was much too complicated. Maybe if Leo had a few years, he could decipher the markings and figure out the right combination, but he didn’t even have a few seconds.

He was out of time. Out of luck. And his friends were going to die.

A problem you cannot solve, said a voice in his mind.

Nemesis…she’d told him to expect this moment. Leo thrust his hand in his pocket and brought out the fortune cookie. The goddess had warned him of a great price for her help—as great as losing an eye. But if he didn’t try, his friends would die.

“I need the access code for this sphere,” he said.

He broke open the cookie.

LEO UNFURLED THE LITTLE STRIP OF PAPER. IT READ:

THAT’S YOUR REQUEST? SERIOUSLY? (OVER)

On the back, the paper said:

YOUR LUCKY NUMBERS ARE: TWELVE, JUPITER, ORION, DELTA, THREE, THETA, OMEGA. (WREAK VENGEANCE UPON GAEA, LEO VALDEZ.)

With trembling fingers, Leo turned the rings.

Outside the gates, Wolf Head growled in frustration. “If friends do not matter to you, perhaps you need more incentive. Perhaps I should destroy these scrolls instead—priceless works by Archimedes!”

The last ring clicked into place. The sphere hummed with power. Leo ran his hands along the surface, sensing tiny buttons and levers awaiting his commands.

Magical and electrical pulses coursed via the Celestial bronze cables, and surged through the entire room.

Leo had never played a musical instrument, but he imagined it must be like this—knowing each key or note so well that you didn’t really think about what your hands were doing. You just concentrated on the kind of sound you wanted to create.

He started small. He focused on one reasonably intact gold sphere down in the main room. The gold sphere shuddered. It grew a tripod of legs and clattered over to the Taser ball. A tiny circular saw popped out of the gold sphere’s head, and it began cutting into Taser ball’s brain.

Leo tried to activate another orb. This one burst in a small mushroom cloud of bronze dust and smoke.

“Oops,” he muttered. “Sorry, Archimedes.”

“What are you doing?” Wolf Head demanded. “Stop your foolishness and surrender!”

“Oh, yes, I surrender!” Leo said. “I’m totally surrendering!”

He tried to take control of a third orb. That one broke too. Leo felt bad about ruining all these ancient inventions, but this was life or death. Frank had accused him of caring more for machines than people, but if it came down to saving old spheres or his friends, there was no choice.

The fourth try went better. A ruby-encrusted orb popped its top and helicopter blades unfolded. Leo was glad Buford the table wasn’t here—he would’ve fallen in love. The ruby orb spun into the air and sailed straight for the cubbyholes. Thin golden arms extended from its middle and snapped up the precious scroll cases.

“Enough!” Wolf Head yelled. “I will destroy the—”

He turned in time to see the ruby sphere take off with the scrolls. It zipped across the room and hovered in the far corner.

“What?!” Wolf Head cried. “Kill the prisoners!”

He must have been talking to the Taser ball. Unfortunately, Taser ball was in no shape to comply. Leo’s gold sphere was sitting on top of its sawed-open head, picking through its gears and wires like it was scooping out a pumpkin.

Thank the gods, Hazel and Frank began to stir.

“Bah!” Wolf Head gestured to Lion Head at the opposite gate. “Come! We will destroy the demigods ourselves.”

“I don’t think so, guys.” Leo turned toward Lion Head. His hands worked the control sphere, and he felt a shock travel through the floor.

Lion Head shuddered and lowered his sword.

Leo grinned. “You’re in Leo World, now.”

Lion Head turned and stormed down the stairs. Instead of advancing on Hazel and Leo, he marched up the opposite stairs and faced his comrade.

“What are you doing?” Wolf Head demanded. “We have to—”

BLONG!

Lion Head slammed his shield into Wolf Head’s chest. He smashed the pommel of his sword into his comrade’s helmet, so Wolf Head became Flat, Deformed, Not Very Happy Wolf Head.

“Stop that!” Wolf Head demanded.

“I cannot!” Lion Head wailed.

Leo was getting the hang of it now. He commanded both suits of armor to drop their swords and shields and slap each other repeatedly.

“Valdez!” called Wolf Head in a warbling voice. “You will die for this!”

“Yeah,” Leo called out. “Who’s possessing who now, Casper?”

The machine men tumbled down the stairs, and Leo forced them to jitterbug like 1920s flappers. Their joints began smoking. The other spheres around the room began to pop. Too much energy was surging through the ancient system. The control sphere in Leo’s hand grew uncomfortably warm.

“Frank, Hazel!” Leo shouted. “Take cover!”

His friends were still dazed, staring in amazement at the jitterbugging metal guys, but they got his warning. Frank pulled Hazel under the nearest table and shielded her with his body.

One last twist of the sphere, and Leo sent a massive jolt through the system. The armored warriors blew apart. Rods, pistons, and bronze shards flew everywhere. On all the tables, spheres popped like hot soda cans. Leo’s gold sphere froze. His flying ruby orb dropped to the floor with the scroll cases.

The room was suddenly quiet except for a few random sparks and sizzles. The air smelled like burning car engines. Leo raced down the stairs and found Frank and Hazel safe under their table. He had never been so happy to see those two hugging.

“You’re alive!” he said.

Hazel’s left eye twitched, maybe from the Taser shock. Otherwise she looked okay. “Uh, what exactly happened?”

“Archimedes came through!” Leo said. “Just enough power left in those old machines for one final show. Once I had the access code, it was easy.”

He patted the control sphere, which was steaming in a bad way. Leo didn’t know if it could be fixed, but at the moment he was too relieved to care.

“The eidolons,” Frank said. “Are they gone?”

Leo grinned. “My last command overloaded their kill switches—basically locked down all their circuits and melted their cores.”

“In English?” Frank asked.

“I trapped the eidolons inside the wiring,” Leo said. “Then I melted them. They won’t be bothering anyone again.”

Leo helped his friends to their feet.

“You saved us,” Frank said.

“Don’t sound so surprised.” Leo glanced around the destroyed workshop. “Too bad all this stuff got wrecked, but at least I salvaged the scrolls. If I can get them back to Camp Half-Blood, maybe I can learn how to recreate Archimedes’s inventions.”

Hazel rubbed the side of her head. “But I don’t understand. Where is Nico? That tunnel was supposed to lead us to Nico.”

Leo had almost forgotten why they’d come down here in the first place. Nico obviously wasn’t here. The place was a dead end. So why… ?

“Oh.” He felt like there was a buzz-saw sphere on his own head, pulling out his wires and gears. “Hazel, how exactly were you tracking Nico? I mean, could you just sense him nearby because he was your brother?”

She frowned, still looking a bit wobbly from her electric shock treatment. “Not—not totally. Sometimes I can tell when he’s close, but, like I said, Rome is so confusing, so much interference because of all the tunnels and caves—”

“You tracked him with your metal-finding senses,” Leo guessed. “His sword?”

She blinked. “How did you know?”

“You’d better come here.” He led Hazel and Frank up to the control room and pointed to the black sword.

“Oh. Oh, no.” Hazel would’ve collapsed if Frank hadn’t caught her. “But that’s impossible! Nico’s sword was with him in the bronze jar. Percy saw it in his dream!”

“Either the dream was wrong,” Leo said, “or the giants moved the sword here as a decoy.”

“So this was a trap,” Frank said. “We were lured here.”

“But why?” Hazel cried. “Where’s my brother?”

A hissing sound filled the control booth. At first, Leo thought the eidolons were back. Then he realized the bronze mirror on the table was steaming.

Ah, my poor demigods. The sleeping face of Gaea appeared in the mirror. As usual, she spoke without moving her mouth, which could only have been creepier if she’d had a ventriloquism puppet. Leo hated those things.

You had your choice, Gaea said. Her voice echoed through the room. It seemed to be coming not just from the mirror, but from the stone walls as well.

Leo realized she was all around them. Of course. They were in the earth. They’d gone to all the trouble of building the Argo II so they could travel by sea and air, and they’d ended up in the earth anyway.

I offered salvation to all of you, Gaea said. You could have turned back. Now it is too late. You’ve come to the ancient lands where I am strongest—where I will wake.

Leo pulled a hammer from his tool belt. He whacked the mirror. Being metal, it just quivered like a tea tray, but it felt good to smash Gaea in the nose.

“In case you haven’t noticed, Dirt Face,” he said, “your little ambush failed. Your three eidolons got melted in bronze, and we’re fine.”

Gaea laughed softly. Oh, my sweet Leo. You three have been separated from your friends. That was the whole point.

The workshop door slammed shut.

You are trapped in my embrace, Gaea said. Meanwhile, Annabeth Chase faces her death alone, terrified and crippled, at the hands of her mother’s greatest enemy.

The image in the mirror changed. Leo saw Annabeth sprawled on the floor of a dark cavern, holding up her bronze knife as if warding off a monster. Her face was gaunt. Her leg was wrapped up in some sort of splint. Leo couldn’t see what she was looking at, but it was obviously something horrible. He wanted to believe the image was a lie, but he had a bad feeling it was real, and it was happening right now.

The others, Gaea said, Jason Grace, Piper McLean, and my dear friend Percy Jackson—they will perish within minutes.

The scene changed again. Percy was holding Riptide, leading Jason and Piper down a spiral staircase into the darkness.

Their powers will betray them, Gaea said. They will die in their own elements. I almost hoped they would survive. They would have made a better sacrifice. But alas, Hazel and Frank, you will have to do. My minions will collect you shortly and bring you to the ancient place. Your blood will awaken me at last. Until then, I will allow you to watch your friends perish. Please…enjoy this last glimpse of your failed quest.

Leo couldn’t stand it. His hand glowed white hot. Hazel and Frank scrambled back as he pressed his palm against the mirror and melted it into a puddle of bronze goo.

The voice of Gaea went silent. Leo could only hear the roar of blood in his ears. He took a shaky breath.

“Sorry,” he told his friends. “She was getting annoying.”

“What do we do?” Frank asked. “We have to get out and help the others.”

Leo scanned the workshop, now littered with smoking pieces of broken spheres. His friends still needed him. This was still his show. As long as he had his tool belt, Leo Valdez wasn’t going to sit around helplessly watching the Demigod Death Channel.

“I’ve got an idea,” he said. “But it’s going to take all three of us.”

He started telling them the plan.

PIPER TRIED TO MAKE THE BEST OF THE SITUATION.

Once she and Jason had gotten tired of pacing the deck, listening to Coach Hedge sing “Old MacDonald” (with weapons instead of animals), they decided to have a picnic in the park.

Hedge grudgingly agreed. “Stay where I can see you.”

“What are we, kids?” Jason asked.

Hedge snorted. “Kids are baby goats. They’re cute, and they have redeeming social value. You are definitely not kids.”

They spread their blanket under a willow tree next to a pond. Piper turned over her cornucopia and spilled out an entire meal—neatly wrapped sandwiches, canned drinks, fresh fruit, and (for some reason) a birthday cake with purple icing and candles already lit.

She frowned. “Is it someone’s birthday?”

Jason winced. “I wasn’t going to say anything.”

“Jason!”

“There’s too much going on,” he said. “And honestly…before last month, I didn’t even know when my birthday was. Thalia told me the last time she was at camp.”

Piper wondered what that would be like—not even knowing the day you were born. Jason had been given to Lupa the wolf when he was only two years old. He’d never really known his mortal mom. He’d only been reunited with his sister last winter.

“July First,” Piper said. “The Kalends of July.”

“Yeah.” Jason smirked. “The Romans would find that auspicious—the first day of the month named for Julius Caesar. Juno’s sacred day. Yippee.”

Piper didn’t want to push it, or make a celebration if he didn’t feel like celebrating.

“Sixteen?” she asked.

He nodded. “Oh, boy. I can get my driver’s license.”

Piper laughed. Jason had killed so many monsters and saved the world so many times that the idea of him sweating a driving test seemed ridiculous. She pictured him behind the wheel of some old Lincoln with a STUDENT DRIVER sign on top and a grumpy teacher in the passenger seat with an emergency brake pedal.

“Well?” she urged. “Blow out the candles.”

Jason did. Piper wondered if he’d made a wish—hopefully that he and Piper would survive this quest and stay together forever. She decided not to ask him. She didn’t want to jinx that wish, and she definitely didn’t want to find out that he’d wished for something different.

Since they’d left the Pillars of Hercules yesterday evening, Jason had seemed distracted. Piper couldn’t blame him. Hercules had been a pretty huge disappointment as a big brother, and the old river god Achelous had said some unflattering things about the sons of Jupiter.

Piper stared at the cornucopia. She wondered if Achelous was getting used to having no horns at all. She hoped so. Sure, he had tried to kill them, but Piper still felt bad for the old god. She didn’t understand how such a lonely, depressed spirit could produce a horn of plenty that shot out pineapples and birthday cakes. Could it be that the cornucopia had drained all the goodness out of him? Maybe now that the horn was gone, Achelous would be able to fill up with some happiness and keep it for himself.

She also kept thinking about Achelous’s advice: If you had made it to Rome, the story of the flood would have served you better. She knew the story he was talking about. She just didn’t understand how it would help.

Jason plucked an extinguished candle from his cake. “I’ve been thinking.”

That snapped Piper back to the present. Coming from your boyfriend, I’ve been thinking was kind of a scary line.

“About?” she asked.

“Camp Jupiter,” he said. “All the years I trained there. We were always pushing teamwork, working as a unit. I thought I understood what that meant. But honestly? I was always the leader. Even when I was younger—”

“The son of Jupiter,” Piper said. “Most powerful kid in the legion. You were the star.”

Jason looked uncomfortable, but he didn’t deny it. “Being in this crew of seven…I’m not sure what to do. I’m not used to being one of so many, well, equals. I feel like I’m failing.”

Piper took his hand. “You’re not failing.”

“It sure felt that way when Chrysaor attacked,” Jason said. “I’ve spent most of this trip knocked out and helpless.”

“Come on,” she chided. “Being a hero doesn’t mean you’re invincible. It just means that you’re brave enough to stand up and do what’s needed.”

“And if I don’t know what’s needed?”

“That’s what your friends are for. We’ve all got different strengths. Together, we’ll figure it out.”

Jason studied her. Piper wasn’t sure that he bought what she was saying, but she was glad he could confide in her. She liked that he had a little self-doubt. He didn’t succeed all the time. He didn’t think the universe owed him an apology whenever something went wrong—unlike another son of the sky god she’d recently met.

“Hercules was a jerk,” he said, as if reading her thoughts. “I never want to be like that. But I wouldn’t have had the courage to stand up to him without your taking the lead. You were the hero that time.”

“We can take turns,” she suggested.

“I don’t deserve you.”

“You’re not allowed to say that.”

“Why not?”

“It’s a breakup line. Unless you’re breaking up—”

Jason leaned over and kissed her. The colors of the Roman afternoon suddenly seemed sharper, as if the world had switched to high definition.

“No breakups,” he promised. “I may have busted my head a few times, but I’m not that stupid.”

“Good,” she said. “Now, about that cake—”

Her voice faltered. Percy Jackson was running toward them, and Piper could tell from his expression that he brought bad news.

They gathered on deck so that Coach Hedge could hear the story. When Percy was done, Piper still couldn’t believe it.

“So Annabeth was kidnapped on a motor scooter,” she summed up, “by Gregory Peck and Audrey Hepburn.”

“Not kidnapped, exactly,” Percy said. “But I’ve got this bad feeling.…” He took a deep breath, like he was trying hard not to freak out. “Anyway, she’s—she’s gone. Maybe I shouldn’t have let her, but—”

“You had to,” Piper said. “You knew she had to go alone. Besides, Annabeth is tough and smart. She’ll be fine.”

Piper put some charmspeak in her voice, which maybe wasn’t cool, but Percy needed to be able to focus. If they went into battle, Annabeth wouldn’t want him getting hurt because he was too distracted about her.

His shoulders relaxed a little. “Maybe you’re right. Anyway, Gregory—I mean Tiberinus—said we had less time to rescue Nico than we thought. Hazel and the guys aren’t back yet?”

Piper checked the time on the helm control. She hadn’t realized how late it was getting. “It’s two in the afternoon. We said three o’clock for a rendezvous.”

“At the latest,” Jason said.

Percy pointed at Piper’s dagger. “Tiberinus said you could find Nico’s location…you know, with that.”

Piper bit her lip. The last thing she wanted to do was check Katoptris for more terrifying images.

“I’ve tried,” she said. “The dagger doesn’t always show what I want to see. In fact, it hardly ever does.”

“Please,” Percy said. “Try again.”

He pleaded with those sea-green eyes, like a cute baby seal that needed help. Piper wondered how Annabeth ever won an argument with this guy.

“Fine,” she sighed, and drew her dagger.

“While you’re at it,” said Coach Hedge, “see if you can get the latest baseball scores. Italians don’t cover baseball worth beans.”

“Shh.” Piper studied the bronze blade. The light shimmered. She saw a loft apartment filled with Roman demigods. A dozen of them stood around a dining table as Octavian talked and pointed to a big map. Reyna paced next to the windows, gazing down at Central Park.

“That’s not good,” Jason muttered. “They’ve already set up a forward base in Manhattan.”

“And that map shows Long Island,” Percy said.

“They’re scouting the territory,” Jason guessed. “Discussing invasion routes.”

Piper did not want to see that. She concentrated harder. Light rippled across the blade. She saw ruins—a few crumbling walls, a single column, a stone floor covered with moss and dead vines—all clustered on a grassy hillside dotted with pine trees.

“I was just there,” Percy said. “That’s in the old Forum.”

The view zoomed in. On one side of the stone floor, a set of stairs had been excavated, leading down to a modern iron gate with a padlock. The blade’s image zoomed straight through the doorway, down a spiral stairwell, and into a dark, cylindrical chamber like the inside of a grain silo.

Piper dropped the blade.

“What’s wrong?” Jason asked. “It was showing us something.”

Piper felt like the boat was back on the ocean, rocking under her feet. “We can’t go there.”

Percy frowned. “Piper, Nico is dying. We’ve got to find him. Not to mention, Rome is about to get destroyed.”

Her voice wouldn’t work. She’d kept that vision of the circular room to herself for so long, now she found it impossible to talk about. She had a horrible feeling that explaining it to Percy and Jason wouldn’t change anything. She couldn’t stop what was about to happen.

She picked up the knife again. Its hilt seemed colder than usual.

She forced herself to look at the blade. She saw two giants in gladiator armor sitting on oversized praetors’ chairs. The giants toasted each other with golden goblets as if they’d just won an important fight. Between them stood a large bronze jar.

The vision zoomed in again. Inside the jar, Nico di Angelo was curled in a ball, no longer moving, all the pomegranate seeds eaten.

“We’re too late,” Jason said.

“No,” Percy said. “No, I can’t believe that. Maybe he’s gone into a deeper trance to buy time. We have to hurry.”

The blade’s surface went dark. Piper slipped it back into its sheath, trying to keep her hands from shaking. She hoped that Percy was right and Nico was still alive. On the other hand, she didn’t see how that image connected with the vision of the drowning room. Maybe the giants were toasting each other because she and Percy and Jason were dead.

“We should wait for the others,” she said. “Hazel, Frank, and Leo should be back soon.”

“We can’t wait,” Percy insisted.

Coach Hedge grunted. “It’s just two giants. If you guys want, I can take them.”

“Uh, Coach,” Jason said, “that’s a great offer, but we need you to man the ship—or goat the ship. Whatever.”

Hedge scowled. “And let you three have all the fun?”

Percy gripped the satyr’s arm. “Hazel and the others need you here. When they get back, they’ll need your leadership. You’re their rock.”

“Yeah.” Jason managed to keep a straight face. “Leo always says you’re his rock. You can tell them where we’ve gone and bring the ship around to meet us at the Forum.”

“And here.” Piper unstrapped Katoptris and put it in Coach Hedge’s hands.

The satyr’s eyes widened. A demigod was never supposed to leave her weapon behind, but Piper was fed up with evil visions. She’d rather face her death without any more previews.

“Keep an eye on us with the blade,” she suggested. “And you can check the baseball scores.”

That sealed the deal. Hedge nodded grimly, prepared to do his part for the quest.

“All right,” he said. “But if any giants come this way—”

“Feel free to blast them,” Jason said.

“What about annoying tourists?”

“No,” they all said in unison.

“Bah. Fine. Just don’t take too long, or I’m coming after you with ballistae blazing.”

FINDING THE PLACE WAS EASY. Percy led them right to it, on an abandoned stretch of hillside overlooking the ruined Forum.

Getting in was easy too. Jason’s gold sword cut through the padlock, and the metal gate creaked open. No mortals saw them. No alarms went off. Stone steps spiraled down into the gloom.

“I’ll go first,” Jason said.

“No!” Piper yelped.

Both boys turned toward her.

“Pipes, what is it?” Jason asked. “That image in the blade…you’ve seen it before, haven’t you?”

She nodded, her eyes stinging. “I didn’t know how to tell you. I saw the room down there filling with water. I saw the three of us drowning.”

Jason and Percy both frowned.

“I can’t drown,” Percy said, though he sounded like he was asking a question.

“Maybe the future has changed,” Jason speculated. “In the image you showed us just now, there wasn’t any water.”

Piper wished he was right, but she suspected they wouldn’t be so lucky.

“Look,” Percy said. “I’ll check it out first. It’s fine. Be right back.”

Before Piper could object, he disappeared down the stairwell.

She counted silently as they waited for him to come back. Somewhere around thirty-five, she heard his footsteps, and he appeared at the top, looking more baffled than relieved.

“Good news: no water,” he said. “Bad news: I don’t see any exits down there. And, uh, weird news: well, you should see this.…”

They descended cautiously. Percy took the lead, with Riptide drawn. Piper followed, and Jason walked behind her, guarding their backs. The stairwell was a cramped corkscrew of masonry, no more than six feet in diameter. Even though Percy had given the “all clear,” Piper kept her eyes open for traps. With every turn of the stairs, she anticipated an ambush. She had no weapon, just the cornucopia on a leather cord over her shoulder. If worse came to worst, the boys’ swords wouldn’t do much good in such close quarters. Maybe Piper could shoot their enemies with high-velocity smoked hams.

As they wound their way underground, Piper saw old graffiti gouged into the stones: Roman numerals, names and phrases in Italian. That meant other people had been down here more recently than the Roman Empire, but Piper wasn’t reassured. If monsters were below, they’d ignore mortals, waiting for some nice juicy demigods to come along.

Finally, they reached the bottom.

Percy turned. “Watch this last step.”

He jumped to the floor of the cylindrical room, which was five feet lower than the stairwell. Why would someone design a set of stairs like that? Piper had no idea. Maybe the room and the stairwell had been built during different time periods.

She wanted to turn and exit, but she couldn’t do that with Jason behind her, and she couldn’t just leave Percy down there. She clambered down, and Jason followed.

The room was just like she’d seen it in Katoptris’s blade, except there was no water. The curved walls had once been painted with frescoes, which were now faded to eggshell white with only flecks of color. The domed ceiling was about fifty feet above.

Around the back side of the room, opposite the stairwell, nine alcoves were carved into the wall. Each niche was about five feet off the floor and big enough for a human-sized statue, but each was empty.

The air felt cold and dry. As Percy had said, there were no other exits.

“All right.” Percy raised his eyebrows. “Here’s the weird part. Watch.”

He stepped to the middle of the room.

Instantly, green and blue light rippled across the walls. Piper heard the sound of a fountain, but there was no water. There didn’t seem to be any source of light except for Percy’s and Jason’s blades.

“Do you smell the ocean?” Percy asked.

Piper hadn’t noticed at first. She was standing next to Percy, and he always smelled like the sea. But he was right. The scent of salt water and storm was getting stronger, like a summer hurricane approaching.

“An illusion?” she asked. All of a sudden, she felt strangely thirsty.

“I don’t know,” Percy said. “I feel like there should be water here—lots of water. But there isn’t any. I’ve never been in a place like this.”

Jason moved to the row of niches. He touched the bottom shelf of the nearest one, which was just at his eye level. “This stone…it’s embedded with seashells. This is a nymphaeum.”

Piper’s mouth was definitely getting drier. “A what?”

“We have one at Camp Jupiter,” Jason said, “on Temple Hill. It’s a shrine to the nymphs.”

Piper ran her hand along the bottom of another niche. Jason was right. The alcove was studded with cowries, conches, and scallops. The seashells seemed to dance in the watery light. They were ice-cold to the touch.

Piper had always thought of nymphs as friendly spirits—silly and flirtatious, generally harmless. They got along well with the children of Aphrodite. They loved to share gossip and beauty tips. This place, though, didn’t feel like the canoe lake back at Camp Half-Blood, or the streams in the woods where Piper normally met nymphs. This place felt unnatural, hostile, and very dry.

Jason stepped back and examined the row of alcoves. “Shrines like this were all over the place in Ancient Rome. Rich people had them outside their villas to honor nymphs, to make sure the local water was always fresh. Some shrines were built around natural springs, but most were man-made.”

“So…no actual nymphs lived here?” Piper asked hopefully.

“Not sure,” Jason said. “This place where we’re standing would have been a pool with a fountain. A lot of times, if the nymphaeum belonged to a demigod, he or she would invite nymphs to live there. If the spirits took up residence, that was considered good luck.”

“For the owner,” Percy guessed. “But it would also bind the nymphs to the new water source, which would be great if the fountain was in a nice sunny park with fresh water pumped in through the aqueducts—”

“But this place has been underground for centuries,” Piper guessed. “Dry and buried. What would happen to the nymphs?”

The sound of water changed to a chorus of hissing, like ghostly snakes. The rippling light shifted from sea blue and green to purple and sickly lime. Above them, the nine niches glowed. They were no longer empty.

Standing in each was a withered old woman, so dried up and brittle they reminded Piper of mummies—except mummies didn’t normally move. Their eyes were dark purple, as if the clear blue water of their life source had condensed and thickened inside them. Their fine silk dresses were now tattered and faded. Their hair had once been piled in curls, arranged with jewels in the style of Roman noblewomen, but now their locks were disheveled and dry as straw. If water cannibals actually existed, Piper thought, this is what they looked like.

“What would happen to the nymphs?” said the creature in the center niche.

She was in even worse shape than the others. Her back was hunched like the handle of a pitcher. Her skeletal hands had only the thinnest papery layer of skin. On her head, a battered wreath of golden laurels glinted in her roadkill hair.

She fixed her purple eyes on Piper. “What an interesting question, my dear. Perhaps the nymphs would still be here, suffering, waiting for revenge.”

The next time that she got a chance, Piper swore she would melt down Katoptris and sell it for scrap metal. The stupid knife never showed her the whole story. Sure, she’d seen herself drowning. But if she’d realized that nine desiccated zombie nymphs would be waiting for her, she never would’ve come down here.

She considered bolting for the stairs, but when she turned, the doorway had disappeared. Naturally. Nothing was there now but a blank wall. Piper suspected it wasn’t just an illusion. Besides, she would never make it to the opposite side of the room before the zombie nymphs could jump on them.

Jason and Percy stood to either side of her, their swords ready. Piper was glad to have them close, but she suspected their weapons wouldn’t do any good. She’d seen what would happen in this room. Somehow, these things were going to defeat them.

“Who are you?” Percy demanded.

The central nymph turned her head. “Ah…names. We once had names. I was Hagno, the first of the nine!”

Piper thought it was a cruel joke that a hag like her would be named Hagno, but she decided not to say that.

“The nine,” Jason repeated. “The nymphs of this shrine. There were always nine niches.”

“Of course.” Hagno bared her teeth in a vicious smile. “But we are the original nine, Jason Grace, the ones who attended the birth of your father.”

Jason’s sword dipped. “You mean Jupiter? You were there when he was born?”

“Zeus, we called him then,” Hagno said. “Such a squealing whelp. We attended Rhea in her labor. When the baby arrived, we hid him so that his father, Kronos, would not eat him. Ah, he had lungs, that baby! It was all we could do to drown out the noise so Kronos could not find him. When Zeus grew up, we were promised eternal honors. But that was in the old country, in Greece.”

The other nymphs wailed and clawed at their niches. They seemed to be trapped in them, Piper realized, as if their feet were glued to the stone along with the decorative seashells.

“When Rome rose to power, we were invited here,” Hagno said. “A son of Jupiter tempted us with favors. A new home, he promised. Bigger and better! No down payment, an excellent neighborhood. Rome will last forever.”

“Forever,” the others hissed.

“We gave in to temptation,” Hagno said. “We left our simple wells and springs on Mount Lycaeus and moved here. For centuries, our lives were wonderful! Parties, sacrifices in our honor, new dresses and jewelry every week. All the demigods of Rome flirted with us and honored us.”

The nymphs wailed and sighed.

“But Rome did not last,” Hagno snarled. “The aqueducts were diverted. Our master’s villa was abandoned and torn down. We were forgotten, buried under the earth, but we could not leave. Our life sources were bound to this place. Our old master never saw fit to release us. For centuries, we have withered here in the darkness, thirsty…so thirsty.”

The others clawed at their mouths.

Piper felt her own throat closing up.

“I’m sorry for you,” she said, trying to use charmspeak. “That must have been terrible. But we are not your enemies. If we can help you—”

“Oh, such a sweet voice!” Hagno cried. “Such beautiful features. I was once young like you. My voice was as soothing as a mountain stream. But do you know what happens to a nymph’s mind when she is trapped in the dark, with nothing to feed on but hatred, nothing to drink but thoughts of violence? Yes, my dear. You can help us.”

Percy raised his hand. “Uh…I’m the son of Poseidon. Maybe I can summon a new water source.”

“Ha!” Hagno cried, and the other eight echoed, “Ha! Ha!”

“Indeed, son of Poseidon,” Hagno said. “I know your father well. Ephialtes and Otis promised you would come.”

Piper put her hand on Jason’s arm for balance.

“The giants,” she said. “You’re working for them?”

“They are our neighbors.” Hagno smiled. “Their chambers lie beyond this place, where the aqueduct’s water was diverted for the games. Once we have dealt with you…once you have helped us…the twins have promised we will never suffer again.”

Hagno turned to Jason. “You, child of Jupiter—for the horrible betrayal of your predecessor who brought us here, you shall pay. I know the sky god’s powers. I raised him as a baby! Once, we nymphs controlled the rain above our wells and springs. When I am done with you, we will have that power again. And Percy Jackson, child of the sea god…from you, we will take water, an endless supply of water.”

“Endless?” Percy’s eyes darted from one nymph to the other. “Uh…look, I don’t know about endless. But maybe I could spare a few gallons.”

“And you, Piper McLean.” Hagno’s purple eyes glistened. “So young, so lovely, so gifted with your sweet voice. From you, we will reclaim our beauty. We have saved our last life force for this day. We are very thirsty. From you three, we shall drink!”

All nine niches glowed. The nymphs disappeared, and water poured from their alcoves—sickly dark water, like oil.

PIPER NEEDED A MIRACLE, not a bedtime story. But right then, standing in shock as black water poured in around her legs, she recalled the legend Achelous had mentioned—the story of the flood.

Not the Noah story, but the Cherokee version that her father used to tell her, with the dancing ghosts and the skeleton dog.

When she was little, she would cuddle next to her dad in his big recliner. She’d gaze out the windows at the Malibu coastline, and her dad would tell her the story he’d heard from Grandpa Tom back on the rez in Oklahoma.

“This man had a dog,” her father always began.

“You can’t start a story that way!” Piper protested. “You have to say Once upon a time.”

Dad laughed. “But this is a Cherokee story. They are pretty straightforward. So, anyway, this man had a dog. Every day the man took his dog to the edge of the lake to get water, and the dog would bark furiously at the lake, like he was mad at it.”

“Was he?”

“Be patient, sweetheart. Finally the man got very annoyed with his dog for barking so much, and he scolded it. ‘Bad dog! Stop barking at the water. It’s only water!’ To his surprise, the dog looked right at him and began to talk.”

“Our dog can say Thank you,” Piper volunteered. “And she can bark Out.”

“Sort of,” her dad agreed. “But this dog spoke entire sentences. The dog said, ‘One day soon, the storms will come. The waters will rise, and everyone will drown. You can save yourself and your family by building a raft, but first you will need to sacrifice me. You must throw me into the water.’”

“That’s terrible!” Piper said. “I would never drown my dog!”

“The man probably said the same thing. He thought the dog was lying—I mean, once he got over the shock that his dog could talk. When he protested, the dog said, ‘If you don’t believe me, look at the scruff of my neck. I am already dead.’”

“That’s sad! Why are you telling me this?”

“Because you asked me to,” her dad reminded her. And indeed, something about the story fascinated Piper. She had heard it dozens of times, but she kept thinking about it.

“Anyway,” said her dad, “the man grabbed the dog by the scruff of its neck and saw that its skin and fur were already coming apart. Underneath was nothing but bones. The dog was a skeleton dog.”

“Gross.”

“I agree. So with tears in his eyes, the man said good-bye to his annoying skeleton dog and tossed it into the water, where it promptly sank. The man built a raft, and when the flood came, he and his family survived.”

“Without the dog.”

“Yes. Without the dog. When the rains subsided, and the raft landed, the man and his family were the only ones alive. The man heard sounds from the other side of a hill—like thousands of people laughing and dancing—but when he raced to the top, alas, down below he saw nothing except bones littering the ground—thousands of skeletons of all the people who had died in the flood. He realized the ghosts of the dead had been dancing. That was the sound he heard.”

Piper waited. “And?”

“And, nothing. The end.”

“You can’t end it that way! Why were the ghosts dancing?”

“I don’t know,” Dad said. “Your grandfather never felt the need to explain. Maybe the ghosts were happy that one family had survived. Maybe they were enjoying the afterlife. They’re ghosts. Who can say?”

Piper was very unsatisfied with that. She had so many unanswered questions. Did the family ever find another dog? Obviously not all dogs drowned, because she herself had a dog.

She couldn’t shake the story. She never looked at dogs the same way, wondering if one of them might be a skeleton dog. And she didn’t understand why the family had to sacrifice their dog to survive. Sacrificing yourself to save your family seemed like a noble thing—a very doglike thing to do.

Now, in the nymphaeum in Rome, as the dark water rose to her waist, Piper wondered why the river god Achelous had mentioned that story.

She wished she had a raft, but she feared she was more like the skeleton dog. She was already dead.

THE BASIN FILLED WITH ALARMING SPEED. Piper, Jason, and Percy pounded on the walls, looking for an exit, but they found nothing. They climbed into the alcoves to gain some height, but with water pouring out of each niche, it was like trying to balance at the edge of a waterfall. Even as Piper stood in a niche, the water was soon up to her knees. From the floor, it was probably eight feet deep and rising fast.

“I could try lightning,” Jason said. “Maybe blast a hole in the roof?”

“That could bring down the whole room and crush us,” Piper said.

“Or electrocute us,” Percy added.

“Not many choices,” Jason said.

“Let me search the bottom,” Percy said. “If this place was built as a fountain, there has to be a way to drain the thing. You guys, check the niches for secret exits. Maybe the seashells are knobs, or something.” It was a desperate idea, but Piper was glad for something to do.

Percy jumped in the water. Jason and Piper climbed from niche to niche, kicking and pounding, wiggling seashells embedded in the stone; but they had no luck.

Sooner than Piper expected, Percy broke the surface, gasping and flailing. She offered her hand, and he almost pulled her in before she could help him up.

“Couldn’t breathe,” he choked. “The water…not normal. Hardly made it back.”

The life force of the nymphs, Piper thought. It was so poisoned and malicious, even a son of the sea god couldn’t control it.

As the water rose around her, Piper felt it affecting her too. Her leg muscles trembled like she’d been running for miles. Her hands turned wrinkled and dry, despite being in the middle of a fountain.

The boys moved sluggishly. Jason’s face was pale. He seemed to be having trouble holding his sword. Percy was drenched and shivering. His hair didn’t look quite so dark, as if the color was leaching out.

“They’re taking our power,” Piper said. “Draining us.”

“Jason,” Percy coughed, “do the lightning.”

Jason raised his sword. The room rumbled, but no lightning appeared. The roof didn’t break. Instead, a miniature rainstorm formed at the top of the chamber. Rain poured down, filling the fountain even faster, but it wasn’t normal rain. The stuff was just as dark as the water in the pool. Every drop stung Piper’s skin.

“Not what I wanted,” Jason said.

The water was up to their necks now. Piper could feel her strength fading. Grandpa Tom’s story about the water cannibals was true. Bad nymphs would steal her life.

“We’ll survive,” she murmured to herself, but she couldn’t charmspeak her way out of this. Soon the poisonous water would be over their heads. They’d have to swim, and this stuff was already paralyzing them.

They would drown, just like in the visions she’d seen.

Percy started pushing the water away with the back of his hand, like he was shooing a bad dog. “Can’t—can’t control it!”

You will need to sacrifice me, the skeleton dog had said in the story. You must throw me into the water.

Piper felt like someone had grabbed the scruff of her neck and exposed the bones. She clutched her cornucopia.

“We can’t fight this,” she said. “If we hold back, that just makes us weaker.”

“What do you mean?” Jason shouted over the rain.

The water was up to their chins. Another few inches, and they’d have to swim. But the water wasn’t halfway to the ceiling yet. Piper hoped that meant that they still had time.

“The horn of plenty,” she said. “We have to overwhelm the nymphs with fresh water, give them more than they can use. If we can dilute this poisonous stuff—”

“Can your horn do that?” Percy struggled to keep his head above water, which was obviously a new experience for him. He looked scared out of his mind.

“Only with your help.” Piper was beginning to understand how the horn worked. The good stuff it produced didn’t come from nowhere. She’d only been able to bury Hercules in groceries when she had concentrated on all her positive experiences with Jason.

To create enough clean fresh water to fill this room, she needed to go even deeper, tap her emotions even more. Unfortunately, she was losing her ability to focus.

“I need you both to channel everything you’ve got into the cornucopia,” she said. “Percy, think about the sea.”

“Salt water?”

“Doesn’t matter! As long as it’s clean. Jason, think about rainstorms—much more rain. Both of you hold the cornucopia.”

They huddled together as the water lifted them off their ledges. Piper tried to remember the safety lessons her dad had given her when they had started surfing. To help someone who’s drowning, you put your arm around them from behind and kick your legs in front of you, moving backward like you’re doing the backstroke. She wasn’t sure if the same strategy could work with two other people, but she put one arm around each boy and tried to keep them afloat as they held the cornucopia between them.

Nothing happened. The rain came down in sheets, still dark and acidic.

Piper’s legs felt like lead. The rising water swirled, threatening to pull her under. She could feel her strength fading.

“No good!” Jason yelled, spitting water.

“We’re getting nowhere,” Percy agreed.

“You have to work together,” Piper cried, hoping she was right. “Both of you think of clean water—a storm of water. Don’t hold anything back. Picture all your power, all your strength leaving you.”

“That’s not hard!” Percy said.

“But force it out!” she said. “Offer up everything, like—like you’re already dead, and your only goal is to help the nymphs. It’s got to be a gift…a sacrifice.”

They got quiet at that word.

“Let’s try again,” Jason said. “Together.”

This time Piper bent all her concentration toward the horn of plenty as well. The nymphs wanted her youth, her life, her voice? Fine. She gave it up willingly and imagined all of her power flooding out of her.

I’m already dead, she told herself, as calm as the skeleton dog. This is the only way.

Clear water blasted from the horn with such force, it pushed them against the wall. The rain changed to a white torrent, so clean and cold, it made Piper gasp.

“It’s working!” Jason cried.

“Too well,” Percy said. “We’re filling the room even faster!”

He was right. The water rose so quickly, the roof was now only a few feet away. Piper could’ve reached up and touched the miniature rain clouds.

“Don’t stop!” she said. “We have to dilute the poison until the nymphs are cleansed.”

“What if they can’t be cleansed?” Jason asked. “They’ve been down here turning evil for thousands of years.”

“Just don’t hold back,” Piper said. “Give everything. Even if we go under—”

Her head hit the ceiling. The rainclouds dissipated and melted into the water. The horn of plenty kept blasting out a clean torrent.

Piper pulled Jason closer and kissed him.

“I love you,” she said.

The words just poured out of her, like the water from the cornucopia. She couldn’t tell what his reaction was, because then they were underwater.

She held her breath. The current roared in her ears. Bubbles swirled around her. Light still rippled through the room, and Piper was surprised she could see it. Was the water getting clearer?

Her lungs were about to burst, but Piper poured her last energy into the cornucopia. Water continued to stream out, though there was no room for more. Would the walls crack under the pressure?

Piper’s vision went dark.

She thought the roar in her ears was her own dying heartbeat. Then she realized the room was shaking. The water swirled faster. Piper felt herself sinking.

With her last strength, she kicked upward. Her head broke the surface and she gasped for breath. The cornucopia stopped. The water was draining almost as fast as it had filled the room.

With a cry of alarm, Piper realized that Percy’s and Jason’s faces were still underwater. She hoisted them up. Instantly, Percy gulped and began to thrash, but Jason was as lifeless as a rag doll.

Piper clung to him. She yelled his name, shook him, and slapped his face. She barely noticed when all the water had drained away and left them on the damp floor.

“Jason!” She tried desperately to think. Should she turn him on his side? Slap his back?

“Piper,” Percy said, “I can help.”

He knelt next to her and touched Jason’s forehead. Water gushed from Jason’s mouth. His eyes flew open, and a clap of thunder threw Percy and Piper backward.

When Piper’s vision cleared, she saw Jason sitting up, still gasping, but the color was coming back to his face.

“Sorry,” he coughed. “Didn’t mean to—”

Piper tackled him with a hug. She would have kissed him, but she didn’t want to suffocate him.

Percy grinned. “In case you’re wondering, that was clean water in your lungs. I could make it come out with no problem.”

“Thanks, man.” Jason clasped his hand weakly. “But I think Piper’s the real hero. She saved us all.”

Yes, she did, a voice echoed through the chamber.

The niches glowed. Nine figures appeared, but they were no longer withered creatures. They were young, beautiful nymphs in shimmering blue gowns, their glossy black curls pinned up with silver and gold brooches. Their eyes were gentle shades of blue and green.

As Piper watched, eight of the nymphs dissolved into vapor and floated upward. Only the nymph in the center remained.

“Hagno?” Piper asked.

The nymph smiled. “Yes, my dear. I didn’t think such selflessness existed in mortals…especially in demigods. No offense.”

Percy got to his feet. “How could we take offense? You just tried to drown us and suck out our lives.”

Hagno winced. “Sorry about that. I was not myself. But you have reminded me of the sun and the rain and the streams in the meadows. Percy and Jason, thanks to you, I remembered the sea and the sky. I am cleansed. But mostly, thanks to Piper. She shared something even better than clear running water.” Hagno turned to her. “You have a good nature, Piper. And I’m a nature spirit. I know what I’m talking about.”

Hagno pointed to the other side of the room. The stairs to the surface reappeared. Directly underneath, a circular opening shimmered into existence, like a sewer pipe, just big enough to crawl through. Piper suspected this was how the water had drained out.

“You may return to the surface,” Hagno said. “Or, if you insist, you may follow the waterway to the giants. But choose quickly, because both doors will fade soon after I am gone. That pipe connects to the old aqueduct line, which feeds both this nymphaeum and the hypogeum that the giants call home.”

“Ugh.” Percy pressed on his temples. “Please, no more complicated words.”

“Oh, home is not a complicated word.” Hagno sounded completely sincere. “I thought it was, but now you have unbound us from this place. My sisters have gone to seek new homes…a mountain stream, perhaps, or a lake in a meadow. I will follow them. I cannot wait to see the forests and grasslands again, and the clear running water.”

“Uh,” Percy said nervously, “things have changed up above in the last few thousand years.”

“Nonsense,” Hagno said. “How bad could it be? Pan would not allow nature to become tainted. I can’t wait to see him, in fact.”

Percy looked like he wanted to say something, but he stopped himself.

“Good luck, Hagno,” Piper said. “And thank you.”

The nymph smiled one last time and vaporized.

Briefly, the nymphaeum glowed with a softer light, like a full moon. Piper smelled exotic spices and blooming roses. She heard distant music and happy voices talking and laughing. She guessed she was hearing hundreds of years of parties and celebrations that had been held at this shrine in ancient times, as if the memories had been freed along with the spirits.

“What is that?” Jason asked nervously.

Piper slipped her hand into his. “The ghosts are dancing. Come on. We’d better go meet the giants.”

PERCY WAS TIRED OF WATER.

If he said that aloud, he would probably get kicked out of Poseidon’s Junior Sea Scouts, but he didn’t care.

After barely surviving the nymphaeum, he wanted to go back to the surface. He wanted to be dry and sit in the warm sunshine for a long time—preferably with Annabeth.

Unfortunately, he didn’t know where Annabeth was. Frank, Hazel, and Leo were missing in action. He still had to save Nico di Angelo, assuming the guy wasn’t already dead. And there was that little matter of the giants destroying Rome, waking Gaea, and taking over the world.

Seriously, these monsters and gods were thousands of years old. Couldn’t they take a few decades off and let Percy live his life? Apparently not.

Percy took the lead as they crawled down the drainage pipe. After thirty feet, it opened into a wider tunnel. To their left, somewhere in the distance, Percy heard rumbling and creaking, like a huge machine needed oiling. He had absolutely no desire to find out what was making that sound, so he figured that must be the way to go.

Several hundred feet later, they reached a turn in the tunnel. Percy held up his hand, signaling Jason and Piper to wait. He peeked around the corner.

The corridor opened into a vast room with twenty-foot ceilings and rows of support columns. It looked like the same parking-garage-type area Percy had seen in his dreams, but now much more crowded with stuff.

The creaking and rumbling came from huge gears and pulley systems that raised and lowered sections of the floor for no apparent reason. Water flowed through open trenches (oh, great, more water), powering waterwheels that turned some of the machines. Other machines were connected to huge hamster wheels with hellhounds inside. Percy couldn’t help thinking of Mrs. O’Leary, and how much she would hate being trapped inside one of those.

Suspended from the ceiling were cages of live animals—a lion, several zebras, a whole pack of hyenas, and even an eight-headed hydra. Ancient-looking bronze and leather conveyor belts trundled along with stacks of weapons and armor, sort of like the Amazons’ warehouse in Seattle, except this place was obviously much older and not as well organized.

Leo would love it, Percy thought. The whole room was like one massive, scary, unreliable machine.

“What is it?” Piper whispered.

Percy wasn’t even sure how to answer. He didn’t see the giants, so he gestured for his friends to come forward and take a look.

About twenty feet inside the doorway, a life-size wooden cutout of a gladiator popped up from the floor. It clicked and whirred along a conveyor belt, got hooked on a rope, and ascended through a slot in the roof.

Jason murmured, “What the heck?”

They stepped inside. Percy scanned the room. There were several thousand things to look at, most of them in motion, but one good aspect of being an ADHD demigod was that Percy was comfortable with chaos. About a hundred yards away, he spotted a raised dais with two empty oversized praetor chairs. Standing between them was a bronze jar big enough to hold a person.

“Look.” He pointed it out to his friends.

Piper frowned. “That’s too easy.”

“Of course,” Percy said.

“But we have no choice,” Jason said. “We’ve got to save Nico.”

“Yeah.” Percy started across the room, picking his way around conveyor belts and moving platforms.

The hellhounds in the hamster wheels paid them no attention. They were too busy running and panting, their red eyes glowing like headlights. The animals in the other cages gave them bored looks, as if to say, I’d kill you, but it would take too much energy.

Percy tried to watch out for traps, but everything here looked like a trap. He remembered how many times he’d almost died in the labyrinth a few years ago. He really wished Hazel were here so she could help with her underground skills (and of course so she could be reunited with her brother).

They jumped over a water trench and ducked under a row of caged wolves. They had made it about halfway to the bronze jar when the ceiling opened over them. A platform lowered. Standing on it like an actor, with one hand raised and his head high, was the purple-haired giant Ephialtes.

Just like Percy had seen in his dreams, the Big F was small by giant standards—about twelve feet tall—but he had tried to make up for it with his loud outfit. He’d changed out of the gladiator armor and was now wearing a Hawaiian shirt that even Dionysus would’ve found vulgar. It had a garish print made up of dying heroes, horrible tortures, and lions eating slaves in the Colosseum. The giant’s hair was braided with gold and silver coins. He had a ten-foot spear strapped to his back, which wasn’t a good fashion statement with the shirt. He wore bright white jeans and leather sandals on his…well, not feet, but curved snakeheads. The snakes flicked their tongues and writhed as if they didn’t appreciate holding up the weight of a giant.

Ephialtes smiled at the demigods like he was really, really pleased to see them.

“At last!” he bellowed. “So very happy! Honestly, I didn’t think you’d make it past the nymphs, but it’s so much better that you did. Much more entertaining. You’re just in time for the main event!”

Jason and Piper closed ranks on either side of Percy. Having them there made him feel a little better. This giant was smaller than a lot of monsters he had faced, but something about him made Percy’s skin crawl. Ephialtes’s eyes danced with a crazy light.

“We’re here,” Percy said, which sounded kind of obvious once he had said it. “Let our friend go.”

“Of course!” Ephialtes said. “Though I fear he’s a bit past his expiration date. Otis, where are you?”

A stone’s throw away, the floor opened, and the other giant rose on a platform.

“Otis, finally!” his brother cried with glee. “You’re not dressed the same as me! You’re…” Ephialtes’s expression turned to horror. “What are you wearing?”

Otis looked like the world’s largest, grumpiest ballet dancer. He wore a skin-tight baby-blue leotard that Percy really wished left more to the imagination. The toes of his massive dancing slippers were cut away so that his snakes could protrude. A diamond tiara (Percy decided to be generous and think of it as a king’s crown) was nestled in his green, firecracker-braided hair. He looked glum and miserably uncomfortable, but he managed a dancer’s bow, which couldn’t have been easy with snake feet and a huge spear on his back.

“Gods and Titans!” Ephialtes yelled. “It’s showtime! What are you thinking?”

“I didn’t want to wear the gladiator outfit,” Otis complained. “I still think a ballet would be perfect, you know, while Armageddon is going on.” He raised his eyebrows hopefully at the demigods. “I have some extra costumes—”

“No!” Ephialtes snapped, and for once Percy was in agreement.

The purple-haired giant faced Percy. He grinned so painfully, he looked like he was being electrocuted.

“Please excuse my brother,” he said. “His stage presence is awful, and he has no sense of style.”

“Okay.” Percy decided not to comment on the Hawaiian shirt. “Now, about our friend…”

“Oh, him,” Ephialtes sneered. “We were going to let him finish dying in public, but he has no entertainment value. He’s spent days curled up sleeping. What sort of spectacle is that? Otis, tip over the jar.”

Otis trudged over to the dais, stopping occasionally to do a plié. He knocked over the jar, the lid popped off, and Nico di Angelo spilled out. The sight of his deathly pale face and too-skinny frame made Percy’s heart stop. Percy couldn’t tell whether he was alive or dead. He wanted to rush over and check, but Ephialtes stood in his way.

“Now we have to hurry,” said the Big F. “We should go through your stage directions. The hypogeum is all set!”

Percy was ready to slice this giant in half and get out of there, but Otis was standing over Nico. If a battle started, Nico was in no condition to defend himself. Percy needed to buy him some recovery time.

Jason raised his gold gladius. “We’re not going to be part of any show,” he said. “And what’s a hypo—whatever-you-call-it?”

“Hypogeum!” Ephialtes said. “You’re a Roman demigod, aren’t you? You should know! Ah, but I suppose if we do our job right down here in the underworks, you really wouldn’t know the hypogeum exists.”

“I know that word,” Piper said. “It’s the area under a coliseum. It housed all the set pieces and machinery used to create special effects.”

Ephialtes clapped enthusiastically. “Exactly so! Are you a student of the theater, my girl?”

“Uh…my dad’s an actor.”

“Wonderful!” Ephialtes turned toward his brother. “Did you hear that, Otis?”

“Actor,” Otis murmured. “Everybody’s an actor. No one can dance.”

“Be nice!” Ephialtes scolded. “At any rate, my girl, you’re absolutely right, but this hypogeum is much more than the stageworks for a coliseum. You’ve heard that in the old days some giants were imprisoned under the earth, and from time to time they would cause earthquakes when they tried to break free? Well, we’ve done much better! Otis and I have been imprisoned under Rome for eons, but we’ve kept busy building our very own hypogeum. Now we’re ready to create the greatest spectacle Rome has ever seen—and the last!”

At Otis’s feet, Nico shuddered. Percy felt like a hellhound hamster wheel somewhere in his chest had started moving again. At least Nico was alive. Now they just had to defeat the giants, preferably without destroying the city of Rome, and get out of here to find their friends.

“So!” Percy said, hoping to keep the giants’ attention on him. “Stage directions, you said?”

“Yes!” Ephialtes said. “Now, I know the bounty stipulates that you and the girl Annabeth should be kept alive if possible, but honestly, the girl is already doomed, so I hope you don’t mind if we deviate from the plan.”

Percy’s mouth tasted like bad nymph water. “Already doomed. You don’t mean she’s—”

“Dead?” the giant asked. “No. Not yet. But don’t worry! We’ve got your other friends locked up, you see.”

Piper made a strangled sound. “Leo? Hazel and Frank?”

“Those are the ones,” Ephialtes agreed. “So we can use them for the sacrifice. We can let the Athena girl die, which will please Her Ladyship. And we can use you three for the show! Gaea will be a bit disappointed, but really, this is a win-win. Your deaths will be much more entertaining.”

Jason snarled. “You want entertaining? I’ll give you entertaining.”

Piper stepped forward. Somehow she managed a sweet smile. “I’ve got a better idea,” she told the giants. “Why don’t you let us go? That would be an incredible twist. Wonderful entertainment value, and it would prove to the world how cool you are.”

Nico stirred. Otis looked down at him. His snaky feet flicked their tongues at Nico’s head.

“Plus!” Piper said quickly. “Plus, we could do some dance moves as we’re escaping. Perhaps a ballet number!”

Otis forgot all about Nico. He lumbered over and wagged his finger at Ephialtes. “You see? That’s what I was telling you! It would be incredible!”

For a second, Percy thought Piper was going to pull it off. Otis looked at his brother imploringly. Ephialtes tugged at his chin as if considering the idea.

At last he shook his head. “No…no, I’m afraid not. You see, my girl, I am the anti-Dionysus. I have a reputation to uphold. Dionysus thinks he knows parties? He’s wrong! His revels are tame compared to what I can do. That old stunt we pulled, for instance, when we piled up mountains to reach Olympus—”

“I told you that would never work,” Otis muttered.

“And the time my brother covered himself with meat and ran through an obstacle course of drakons—”

“You said Hephaestus-TV would show it during prime time,” Otis said. “No one even saw me.”

“Well, this spectacle will be even better,” Ephialtes promised. “The Romans always wanted bread and circuses—food and entertainment! As we destroy their city, I will offer them both. Behold, a sample!”

Something dropped from the ceiling and landed at Percy’s feet: a loaf of sandwich bread in a white plastic wrapper with red and yellow dots.

Percy picked it up. “Wonder bread?”

“Magnificent, isn’t it?” Ephialtes’s eyes danced with crazy excitement. “You can keep that loaf. I plan on distributing millions to the people of Rome as I obliterate them.”

“Wonder bread is good,” Otis admitted. “Though the Romans should dance for it.”

Percy glanced over at Nico, who was just starting to move. Percy wanted him to be at least conscious enough to crawl out of the way when the fighting started. And Percy needed more information from the giants about Annabeth, and where his other friends were being kept.

“Maybe,” Percy ventured, “you should bring our other friends here. You know, spectacular deaths…the more the merrier, right?”

“Hmm.” Ephialtes fiddled with a button on his Hawaiian shirt. “No. It’s really too late to change the choreography. But never fear. The circuses will be marvelous! Ah…not the modern sort of circus, mind you. That would require clowns, and I hate clowns.”

“Everyone hates clowns,” Otis said. “Even other clowns hate clowns.”

“Exactly,” his brother agreed. “But we have much better entertainment planned! The three of you will die in agony, up above, where all the gods and mortals can watch. But that’s just the opening ceremony! In the old days, games went on for days or weeks. Our spectacle—the destruction of Rome—will go on for one full month until Gaea awakens.”

“Wait,” Jason said. “One month, and Gaea wakes up?”

Ephialtes waved away the question. “Yes, yes. Something about August First being the best date to destroy all humanity. Not important! In her infinite wisdom, the Earth Mother has agreed that Rome can be destroyed first, slowly and spectacularly. It’s only fitting!”

“So…” Percy couldn’t believe he was talking about the end of the world with a loaf of Wonder bread in his hand. “You’re Gaea’s warm-up act.”

Ephialtes’s face darkened. “This is no warm-up, demigod! We’ll release wild animals and monsters into the streets. Our special effects department will produce fires and earthquakes. Sinkholes and volcanoes will appear randomly out of nowhere! Ghosts will run rampant.”

“The ghost thing won’t work,” Otis said. “Our focus groups say it won’t pull ratings.”

“Doubters!” Ephialtes said. “This hypogeum can make anything work!”

Ephialtes stormed over to a big table covered with a sheet. He pulled the sheet away, revealing a collection of levers and knobs almost as complicated-looking as Leo’s control panel on the Argo II.

“This button?” Ephialtes said. “This one will eject a dozen rabid wolves into the Forum. And this one will summon automaton gladiators to battle tourists at the Trevi Fountain. This one will cause the Tiber to flood its banks so we can reenact a naval battle right in the Piazza Navona! Percy Jackson, you should appreciate that, as a son of Poseidon!”

“Uh…I still think the letting us go idea is better,” Percy said.

“He’s right,” Piper tried again. “Otherwise we get into this whole confrontation thing. We fight you. You fight us. We wreck your plans. You know, we’ve defeated a lot of giants lately. I’d hate for things to get out of control.”

Ephialtes nodded thoughtfully. “You’re right.”

Piper blinked. “I am?”

“We can’t let things get out of control,” the giant agreed. “Everything has to be timed perfectly. But don’t worry. I’ve choreographed your deaths. You’ll love it.”

Nico started to crawl away, groaning. Percy wanted him to move faster and to groan less. He considered throwing his Wonder bread at him.

Jason switched his sword hand. “And if we refuse to cooperate with your spectacle?”

“Well, you can’t kill us.” Ephialtes laughed, as if the idea was ridiculous. “You have no gods with you, and that’s the only way you could hope to triumph. So really, it would be much more sensible to die painfully. Sorry, but the show must go on.”

This giant was even worse than that sea god Phorcys back in Atlanta, Percy realized. Ephialtes wasn’t so much the anti-Dionysus. He was Dionysus gone crazy on steroids. Sure, Dionysus was the god of revelry and out-of-control parties. But Ephialtes was all about riot and ruin for pleasure.

Percy looked at his friends. “I’m getting tired of this guy’s shirt.”

“Combat time?” Piper grabbed her horn of plenty.

“I hate Wonder bread,” Jason said.

Together, they charged.

THINGS WENT WRONG IMMEDIATELY.The giants vanished in twin puffs of smoke. They reappeared halfway across the room, each in a different spot. Percy sprinted toward Ephialtes, but slots in the floor opened under his feet, and metal walls shot up on either side, separating him from his friends.

The walls started closing in on him like the sides of a vise grip. Percy jumped up and grabbed the bottom of the hydra’s cage. He caught a brief glimpse of Piper leaping across a hopscotch pattern of fiery pits, making her way toward Nico, who was dazed and weaponless and being stalked by a pair of leopards.

Meanwhile Jason charged at Otis, who pulled his spear and heaved a great sigh, as if he would much rather dance Swan Lake than kill another demigod.

Percy registered all this in a split second, but there wasn’t much he could do about it. The hydra snapped at his hands. He swung and dropped, landing in a grove of painted plywood trees that sprang up from nowhere. The trees changed positions as he tried to run through them, so he slashed down the whole forest with Riptide.

“Wonderful!” Ephialtes cried. He stood at his control panel about sixty feet to Percy’s left. “We’ll consider this a dress rehearsal. Shall I unleash the hydra onto the Spanish Steps now?”

He pulled a lever, and Percy glanced behind him. The cage he had just been hanging from was now rising toward a hatch in the ceiling. In three seconds it would be gone. If Percy attacked the giant, the hydra would ravage the city.

Cursing, he threw Riptide like a boomerang. The sword wasn’t designed for that, but the Celestial bronze blade sliced through the chains suspending the hydra. The cage tumbled sideways. The door broke open, and the monster spilled out—right in front of Percy.

“Oh, you are a spoilsport, Jackson!” Ephialtes called. “Very well. Battle it here, if you must, but your death won’t be nearly as good without the cheering crowds.”

Percy stepped forward to confront the monster—then realized he’d just thrown his weapon away. A bit of bad planning on his part.

He rolled to one side as all eight hydra heads spit acid, turning the floor where he’d been standing into a steaming crater of melted stone. Percy really hated hydras. It was almost a good thing that he’d lost his sword, since his gut instinct would’ve been to slash at the heads, and a hydra simply grew two new ones for each one it lost.

The last time he’d faced a hydra, he’d been saved by a battleship with bronze cannons that blasted the monster to pieces. That strategy couldn’t help him now…or could it?

The hydra lashed out. Percy ducked behind a giant hamster wheel and scanned the room, looking for the boxes he’d seen in his dream. He remembered something about rocket launchers.

At the dais, Piper stood guard over Nico as the leopards advanced. She aimed her cornucopia and shot a pot roast over the cats’ heads. It must have smelled pretty good, because the leopards raced after it.

About eighty feet to Piper’s right, Jason battled Otis, sword against spear. Otis had lost his diamond tiara and looked angry about it. He probably could have impaled Jason several times, but the giant insisted on doing a pirouette with every attack, which slowed him down.

Meanwhile Ephialtes laughed as he pushed buttons on his control board, cranking the conveyor belts into high gear and opening random animal cages.

The hydra charged around the hamster wheel. Percy swung behind a column, grabbed a garbage bag full of Wonder bread, and threw it at the monster. The hydra spit acid, which was a mistake. The bag and wrappers dissolved in midair. The Wonder bread absorbed the acid like fire extinguisher foam and splattered against the hydra, covering it in a sticky, steaming layer of high-calorie poisonous goo.

As the monster reeled, shaking its heads and blinking Wonder acid out of its eyes, Percy looked around desperately. He didn’t see the rocket-launcher boxes, but tucked against the back wall was a strange contraption like an artist’s easel, fitted with rows of missile launchers. Percy spotted a bazooka, a grenade launcher, a giant Roman candle, and a dozen other wicked-looking weapons. They all seemed to be wired together, pointing in the same direction and connected to a single bronze lever on the side. At the top of the easel, spelled in carnations, were the words: HAPPY DESTRUCTION, ROME!

Percy bolted toward the device. The hydra hissed and charged after him.

“I know!” Ephialtes cried out happily. “We can start with explosions along the Via Labicana! We can’t keep our audience waiting forever.”

Percy scrambled behind the easel and turned it toward Ephialtes. He didn’t have Leo’s skill with machines, but he knew how to aim a weapon.

The hydra barreled toward him, blocking his view of the giant. Percy hoped this contraption would have enough firepower to take down two targets at once. He tugged at the lever. It didn’t budge.

All eight hydra heads loomed over him, ready to melt him into a pool of sludge. He tugged the lever again. This time the easel shook and the weapons began to hiss.

“Duck and cover!” Percy yelled, hoping his friends got the message.

Percy leaped to one side as the easel fired. The sound was like a fiesta in the middle of an exploding gunpowder factory. The hydra vaporized instantly. Unfortunately, the recoil knocked the easel sideways and sent more projectiles shooting all over the room. A chunk of ceiling collapsed and crushed a waterwheel. More cages snapped off their chains, unleashing two zebras and a pack of hyenas. A grenade exploded over Ephialtes’s head, but it only blasted him off his feet. The control board didn’t even look damaged.

Across the room, sandbags rained down around Piper and Nico. Piper tried to pull Nico to safety, but one of the bags caught her shoulder and knocked her down.

“Piper!” Jason cried. He ran toward her, completely forgetting about Otis, who aimed his spear at Jason’s back.

“Look out!” Percy yelled.

Jason had fast reflexes. As Otis threw, Jason rolled. The point sailed over him and Jason flicked his hand, summoning a gust of wind that changed the spear’s direction. It flew across the room and skewered Ephialtes through his side just as he was getting to his feet.

“Otis!” Ephialtes stumbled away from his control board, clutching the spear as he began to crumble into monster dust. “Will you please stop killing me!”

“Not my fault!”

Otis had barely finished speaking when Percy’s missile-launching contraption spit out one last sphere of Roman candle fire. The fiery pink ball of death (naturally it had to be pink) hit the ceiling above Otis and exploded in a beautiful shower of light. Colorful sparks pirouetted gracefully around the giant. Then a ten-foot section of roof collapsed and crushed him flat.

Jason ran to Piper’s side. She yelped when he touched her arm. Her shoulder looked unnaturally bent, but she muttered, “Fine. I’m fine.” Next to her, Nico sat up, looking around him in bewilderment as if just realizing he’d missed a battle.

Sadly, the giants weren’t finished. Ephialtes was already re-forming, his head and shoulders rising from the mound of dust. He tugged his arms free and glowered at Percy.

Across the room, the pile of rubble shifted, and Otis busted out. His head was slightly caved in. All the firecrackers in his hair had popped, and his braids were smoking. His leotard was in tatters, which was just about the only way it could’ve looked less attractive on him.

“Percy!” Jason shouted. “The controls!”

Percy unfroze. He found Riptide in his pocket again, uncapped his sword, and lunged for the switchboard. He slashed his blade across the top, decapitating the controls in a shower of bronze sparks.

“No!” Ephialtes wailed. “You’ve ruined the spectacle!”

Percy turned too slowly. Ephialtes swung his spear like a bat and smacked him across the chest. He fell to his knees, the pain turning his stomach to lava.

Jason ran to his side, but Otis lumbered after him. Percy managed to rise and found himself shoulder to shoulder with Jason. Over by the dais, Piper was still on the floor, unable to get up. Nico was barely conscious.

The giants were healing, getting stronger by the minute. Percy was not.

Ephialtes smiled apologetically. “Tired, Percy Jackson? As I said, you cannot kill us. So I guess we’re at an impasse. Oh, wait…no we’re not! Because we can kill you!”

“That,” Otis grumbled, picking up his fallen spear, “is the first thing sensible thing you’ve said all day, brother.”

The giants pointed their weapons, ready to turn Percy and Jason into a demigod-kabob.

“We won’t give up,” Jason growled. “We’ll cut you into pieces like Jupiter did to Saturn.”

“That’s right,” Percy said. “You’re both dead. I don’t care if we have a god on our side or not.”

“Well, that’s a shame,” said a new voice.

To his right, another platform lowered from the ceiling. Leaning casually on a pinecone-topped staff was a man in a purple camp shirt, khaki shorts, and sandals with white socks. He raised his broad-brimmed hat, and purple fire flickered in his eyes. “I’d hate to think I made a special trip for nothing.”

PERCY HAD NEVER THOUGHT OF MR. D as a calming influence, but suddenly everything got quiet. The machines ground to a halt. The wild animals stopped growling.

The two leopards paced over—still licking their lips from Piper’s pot roast—and butted their heads affectionately against the god’s legs. Mr. D scratched their ears.

“Really, Ephialtes,” he chided. “Killing demigods is one thing. But using leopards for your spectacle? That’s over the line.”

The giant made a squeaking sound. “This—this is impossible. D-D—”

“It’s Bacchus, actually, my old friend,” said the god. “And of course it’s possible. Someone told me there was a party going on.”

He looked the same as he had in Kansas, but Percy still couldn’t get over the differences between Bacchus and his old not-so-much-of-a-friend Mr. D.

Bacchus was meaner and leaner, with less of a potbelly. He had longer hair, more spring in his step, and a lot more anger in his eyes. He even managed to make a pinecone on a stick look intimidating.

Ephialtes’s spear quivered. “You—you gods are doomed! Be gone, in the name of Gaea!”

“Hmm.” Bacchus sounded unimpressed. He strolled through the ruined props, platforms, and special effects.

“Tacky.” He waved his hand at a painted wooden gladiator, then turned to a machine that looked like an oversized rolling pin studded with knives. “Cheap. Boring. And this…” He inspected the rocket-launching contraption, which was still smoking. “Tacky, cheap, and boring. Honestly, Ephialtes. You have no sense of style.”

“STYLE?” The giant’s face flushed. “I have mountains of style. I define style. I—I—”

“My brother oozes style,” Otis suggested.

“Thank you!” Ephialtes cried.

Bacchus stepped forward, and the giants stumbled back. “Have you two gotten shorter?” asked the god.

“Oh, that’s low,” Ephialtes growled. “I’m quite tall enough to destroy you, Bacchus! You gods, always hiding behind your mortal heroes, trusting the fate of Olympus to the likes of these.”

He sneered at Percy.

Jason hefted his sword. “Lord Bacchus, are we going to kill these giants or what?”

“Well, I certainly hope so,” Bacchus said. “Please, carry on.”

Percy stared at him. “Didn’t you come here to help?”

Bacchus shrugged. “Oh, I appreciated the sacrifice at sea. A whole ship full of Diet Coke. Very nice. Although I would’ve preferred Diet Pepsi.”

“And six million in gold and jewels,” Percy muttered.

“Yes,” Bacchus said, “although with demigod parties of five or more the gratuity is included, so that wasn’t necessary.”

“What?”

“Never mind,” Bacchus said. “At any rate, you got my attention. I’m here. Now I need to see if you’re worthy of my help. Go ahead. Battle. If I’m impressed, I’ll jump in for the grand finale.”

“We speared one,” Percy said. “Dropped the roof on the other. What do you consider impressive?”

“Ah, a good question…” Bacchus tapped his thyrsus. Then he smiled in a way that made Percy think, Uh-oh. “Perhaps you need inspiration! The stage hasn’t been properly set. You call this a spectacle, Ephialtes? Let me show you how it’s done.”

The god dissolved into purple mist. Piper and Nico disappeared.

“Pipes!” Jason yelled. “Bacchus, where did you—?”

The entire floor rumbled and began to rise. The ceiling opened in a series of panels. Sunlight poured in. The air shimmered like a mirage, and Percy heard the roar of a crowd above him.

The hypogeum ascended through a forest of weathered stone columns, into the middle of a ruined coliseum.

Percy’s heart did a somersault. This wasn’t just any coliseum. It was the Colosseum. The giants’ special effects machines had gone into overtime, laying planks across ruined support beams so the arena had a proper floor again. The bleachers repaired themselves until they were gleaming white. A giant red-and-gold canopy extended overhead to provide shade from the afternoon sun. The emperor’s box was draped with silk, flanked by banners and golden eagles. The roar of applause came from thousands of shimmering purple ghosts, the Lares of Rome brought back for an encore performance.

Vents opened in the floor and sprayed sand across the arena. Huge props sprang up—garage-size mountains of plaster, stone columns, and (for some reason) life-size plastic barnyard animals. A small lake appeared to one side. Ditches crisscrossed the arena floor in case anyone was in the mood for trench warfare. Percy and Jason stood together facing the twin giants.

“This is a proper show!” boomed the voice of Bacchus. He sat in the emperor’s box wearing purple robes and golden laurels. At his left sat Nico and Piper, her shoulder being tended by a nymph in a nurse’s uniform. At Bacchus’s right crouched a satyr, offering up Doritos and grapes. The god raised a can of Diet Pepsi and the crowd went respectfully quiet.

Percy glared up at him. “You’re just going to sit there?”

“The demigod is right!” Ephialtes bellowed. “Fight us yourself, coward! Um, without the demigods.”

Bacchus smiled lazily. “Juno says she’s assembled a worthy crew of demigods. Show me. Entertain me, heroes of Olympus. Give me a reason to do more. Being a god has its privileges.”

He popped his soda can top, and the crowd cheered.

PERCY HAD FOUGHT MANY BATTLES. He’d even fought in a couple of arenas, but nothing like this. In the huge Colosseum, with thousands of cheering ghosts, the god Bacchus staring down at him, and the two twelve-foot giants looming over him, Percy felt as small and insignificant as a bug. He also felt very angry.

Fighting giants was one thing. Bacchus making it into a game was something else.

Percy remembered what Luke Castellan had told him years ago, when Percy had come back from his very first quest: Didn’t you realize how useless it all is? All the heroics—being pawns of the Olympians?

Percy was almost the same age now as Luke had been then. He could understand how Luke became so spiteful. In the past five years, Percy had been a pawn too many times. The Olympians seemed to take turns using him for their schemes.

Maybe the gods were better than the Titans, or the giants, or Gaea, but that didn’t make them good or wise. It didn’t make Percy like this stupid arena battle.

Unfortunately, he didn’t have much choice. If he was going to save his friends, he had to beat these giants. He had to survive and find Annabeth.

Ephialtes and Otis made his decision easier by attacking. Together, the giants picked up a fake mountain as big as Percy’s New York apartment and hurled it at the demigods.

Percy and Jason bolted. They dove together into the nearest trench and the mountain shattered above them, spraying them with plaster shrapnel. It wasn’t deadly, but it stung like crazy.

The crowd jeered and shouted for blood. “Fight! Fight!”

“I’ll take Otis again?” Jason called over the noise. “Or do you want him this time?”

Percy tried to think. Dividing was the natural course—fighting the giants one-on-one, but that hadn’t worked so well last time. It dawned on him that they needed a different strategy.

This whole trip, Percy had felt responsible for leading and protecting his friends. He was sure Jason felt the same way. They’d worked in small groups, hoping that would be safer. They’d fought as individuals, each demigod doing what he or she did best. But Hera had made them a team of seven for a reason. The few times Percy and Jason had worked together—summoning the storm at Fort Sumter, helping the Argo II escape the Pillars of Hercules, even filling the nymphaeum—Percy had felt more confident, better able to figure out problems, as if he’d been a Cyclops his whole life and suddenly woke up with two eyes.

“We attack together,” he said. “Otis first, because he’s weaker. Take him out quickly and move to Ephialtes. Bronze and gold together—maybe that’ll keep them from re-forming a little longer.”

Jason smiled dryly, like he’d just found out he would die in an embarrassing way.

“Why not?” he agreed. “But Ephialtes isn’t going to stand there and wait while we kill his brother. Unless—”

“Good wind today,” Percy offered. “And there’re some water pipes running under the arena.”

Jason understood immediately. He laughed, and Percy felt a spark of friendship. This guy thought the same way he did about a lot of things.

“On three?” Jason said.

“Why wait?”

They charged out of the trench. As Percy suspected, the twins had lifted another plaster mountain and were waiting for a clear shot. The giants raised it above their heads, preparing to throw, and Percy caused a water pipe to burst at their feet, shaking the floor. Jason sent a blast of wind against Ephialtes’s chest. The purple-haired giant toppled backward and Otis lost his grip on the mountain, which promptly collapsed on top of his brother. Only Ephialtes’s snake feet stuck out, darting their heads around, as if wondering where the rest of their body had gone.

The crowd roared with approval, but Percy suspected Ephialtes was only stunned. They had a few seconds at best.

“Hey, Otis!” he shouted. “The Nutcracker bites!”

“Ahhhhh!” Otis snatched up his spear and threw, but he was too angry to aim straight. Jason deflected it over Percy’s head and into the lake.

The demigods backed toward the water, shouting insults about ballet—which was kind of a challenge, as Percy didn’t know much about it.

Otis barreled toward them empty-handed, before apparently realizing that a) he was empty-handed, and b) charging toward a large body of water to fight a son of Poseidon was maybe not a good idea.

Too late, he tried to stop. The demigods rolled to either side, and Jason summoned the wind, using the giant’s own momentum to shove him into the water. As Otis struggled to rise, Percy and Jason attacked as one. They launched themselves at the giant and brought their blades down on Otis’s head.

The poor guy didn’t even have a chance to pirouette. He exploded into powder on the lake’s surface like a huge packet of drink mix.

Percy churned the lake into a whirlpool. Otis’s essence tried to re-form, but as his head appeared from the water, Jason called lightning and blasted him to dust again.

So far so good, but they couldn’t keep Otis down forever. Percy was already tired from his fight underground. His gut still ached from getting smacked with a spear shaft. He could feel his strength waning, and they still had another giant to deal with.

As if on cue, the plaster mountain exploded behind them. Ephialtes rose, bellowing with anger.

Percy and Jason waited as he lumbered toward them, his spear in hand. Apparently, getting flattened under a plaster mountain had only energized him. His eyes danced with murderous light. The afternoon sun glinted in his coin-braided hair. Even his snake feet looked angry, baring their fangs and hissing.

Jason called down another lightning strike, but Ephialtes caught it on his spear and deflected the blast, melting a life-size plastic cow. He slammed a stone column out of his way like a stack of building blocks.

Percy tried to keep the lake churning. He didn’t want Otis rising to join this fight, but as Ephialtes closed the last few feet, Percy had to switch focus.

Jason and he met the giant’s charge. They lunged around Ephialtes, stabbing and slashing in a blur of gold and bronze, but the giant parried every strike.

“I will not yield!” Ephialtes roared. “You may have ruined my spectacle, but Gaea will still destroy your world!”

Percy lashed out, slicing the giant’s spear in half. Ephialtes wasn’t even fazed. The giant swept low with the blunt end and knocked Percy off his feet. Percy landed hard on his sword arm, and Riptide clattered out of his grip.

Jason tried to take advantage. He stepped inside the giant’s guard and stabbed at his chest, but somehow Ephialtes parried the strike. He sliced the tip of his spear down Jason’s chest, ripping his purple shirt into a vest. Jason stumbled, looking at the thin line of blood down his sternum. Ephialtes kicked him backward.

Up in the emperor’s box, Piper cried out, but her voice was drowned in the roar of the crowd. Bacchus looked on with an amused smile, munching from a bag of Doritos.

Ephialtes towered over Percy and Jason, both halves of his broken spear poised over their heads. Percy’s sword arm was numb. Jason’s gladius had skittered across the arena floor. Their plan had failed.

Percy glanced up at Bacchus, deciding what final curse he would hurl at the useless wine god, when he saw a shape in the sky above the Colosseum—a large dark oval descending rapidly.

From the lake, Otis yelled, trying to warn his brother, but his half-dissolved face could only manage: “Uh-umh-moooo!”

“Don’t worry, brother!” Ephialtes said, his eyes still fixed on the demigods. “I will make them suffer!”

The Argo II turned in the sky, presenting its port side, and green fire blazed from the ballista.

“Actually,” Percy said. “Look behind you.”

He and Jason rolled away as Ephialtes turned and bellowed in disbelief.

Percy dropped into a trench just as the explosion rocked the Colosseum.

When he climbed out again, the Argo II was coming in for a landing. Jason poked his head out from behind his improvised bomb shelter of a plastic horse. Ephialtes lay charred and groaning on the arena floor, the sand around him seared into a halo of glass by the heat of the Greek fire. Otis was floundering in the lake, trying to re-form, but from the arms down he looked like a puddle of burnt oatmeal.

Percy staggered over to Jason and clapped him on the shoulder. The ghostly crowd gave them a standing ovation as the Argo II extended its landing gear and settled on the arena floor. Leo stood at the helm, Hazel and Frank grinning at his side. Coach Hedge danced around the firing platform, pumping his fist in the air and yelling, “That’s what I’m talking about!”

Percy turned to the emperor’s box. “Well?” he yelled at Bacchus. “Was that entertaining enough for you, you wine-breathed little—”

“No need for that.” Suddenly the god was standing right next to him in the arena. He brushed Dorito dust off his purple robes. “I have decided you are worthy partners for this combat.”

“Partners?” Jason growled. “You did nothing!”

Bacchus walked to the edge of the lake. The water instantly drained, leaving an Otis-headed pile of mush. Bacchus picked his way to the bottom and looked up at the crowd. He raised his thyrsus.

The crowd jeered and hollered and pointed their thumbs down. Percy had never been sure whether that meant live or die. He’d heard it both ways.

Bacchus chose the more entertaining option. He smacked Otis’s head with his pinecone staff, and the giant pile of Otismeal disintegrated completely.

The crowd went wild. Bacchus climbed out of the lake and strutted over to Ephialtes, who was still lying spread-eagled, overcooked and smoking.

Again, Bacchus raised his thyrsus.

“DO IT!” the crowd roared.

“DON’T DO IT!” Ephialtes wailed.

Bacchus tapped the giant on the nose, and Ephialtes crumbled to ashes.

The ghosts cheered and threw spectral confetti as Bacchus strode around the stadium with his arms raised triumphantly, exulting in the worship. He grinned at the demigods. “That, my friends, is a show! And of course I did something. I killed two giants!”

As Percy’s friends disembarked from the ship, the crowd of ghosts shimmered and disappeared. Piper and Nico struggled down from the emperor’s box as the Colosseum’s magical renovations began to turn into mist. The arena floor remained solid, but otherwise the stadium looked as if it hadn’t hosted a good giant killing for eons.

“Well,” Bacchus said. “That was fun. You have my permission to continue your voyage.”

“Your permission?” Percy snarled.

“Yes.” Bacchus raised an eyebrow. “Although your voyage may be a little harder than you expect, son of Neptune.”

“Poseidon,” Percy corrected him automatically. “What do you mean about my voyage?”

“You might try the parking lot behind the Emmanuel Building,” Bacchus said. “Best place to break through. Now, good-bye, my friends. And, ah, good luck with that other little matter.”

The god vaporized in a cloud of mist that smelled faintly of grape juice. Jason ran to meet Piper and Nico.

Coach Hedge trotted up to Percy, with Hazel, Frank, and Leo close behind. “Was that Dionysus?” Hedge asked. “I love that guy!”

“You’re alive!” Percy said to the others. “The giants said you were captured. What happened?”

Leo shrugged. “Oh, just another brilliant plan by Leo Valdez. You’d be amazed what you can do with an Archimedes sphere, a girl who can sense stuff underground, and a weasel.”

“I was the weasel,” Frank said glumly.

“Basically,” Leo explained, “I activated a hydraulic screw with the Archimedes device—which is going to be awesome once I install it in the ship, by the way. Hazel sensed the easiest path to drill to the surface. We made a tunnel big enough for a weasel, and Frank climbed up with a simple transmitter that I slapped together. After that, it was just a matter of hacking into Coach Hedge’s favorite satellite channels and telling him to bring the ship around to rescue us. After he got us, finding you was easy, thanks to that godly light show at the Colosseum.”

Percy understood about ten percent of Leo’s story, but he decided it was enough since he had a more pressing question. “Where’s Annabeth?”

Leo winced. “Yeah, about that…she’s still in trouble, we think. Hurt, broken leg, maybe—at least according to this vision Gaea shown us. Rescuing her is our next stop.”

Two seconds before, Percy had been ready to collapse. Now another surge of adrenaline coursed through his body. He wanted to strangle Leo and demand why the Argo II hadn’t sailed off to rescue Annabeth first, but he thought that might sound a little ungrateful.

“Tell me about the vision,” he said. “Tell me everything.”

The floor shook. The wooden planks began to disappear, spilling sand into the pits of the hypogeum below.

“Let’s talk on board,” Hazel suggested. “We’d better take off while we still can.”

They sailed out of the Colosseum and veered south over the rooftops of Rome.

All around the Piazza del Colosseo, traffic had come to a standstill. A crowd of mortals had gathered, probably wondering about the strange lights and sounds that had come from the ruins. As far as Percy could see, none of the giants’ spectacular plans for destruction had come off successfully. The city looked the same as before. No one seemed to notice the huge Greek trireme rising into the sky.

The demigods gathered around the helm. Jason bandaged Piper’s sprained shoulder while Hazel sat at the stern, feeding Nico ambrosia. The son of Hades could barely lift his head. His voice was so quiet, Hazel had to lean in whenever he spoke.

Frank and Leo recounted what had happened in the room with the Archimedes spheres, and the visions Gaea had shown them in the bronze mirror. They quickly decided that their best lead for finding Annabeth was the cryptic advice Bacchus had provided: the Emmanuel Building, whatever that was. Frank started typing at the helm’s computer while Leo tapped furiously at his controls, muttering, “Emmanuel Building. Emmanuel Building.” Coach Hedge tried to help by wrestling with an upside-down street map of Rome.

Percy knelt next to Jason and Piper. “How’s the shoulder?”

Piper smiled. “It’ll heal. Both of you did great.”

Jason elbowed Percy. “Not a bad team, you and me.”

“Better than jousting in a Kansas cornfield,” Percy agreed.

“There it is!” Leo cried, pointing to his monitor. “Frank, you’re amazing! I’m setting course.”

Frank hunched his shoulders. “I just read the name off the screen. Some Chinese tourist marked it on Google Maps.”

Leo grinned at the others. “He reads Chinese.”

“Just a tiny bit,” Frank said.

“How cool is that?”

“Guys,” Hazel broke in. “I hate to interrupt your admiration session, but you should hear this.”

She helped Nico to his feet. He’d always been pale, but now his skin looked like powdered milk. His dark sunken eyes reminded Percy of photos he’d seen of liberated prisoners-of-war, which Percy guessed Nico basically was.

“Thank you,” Nico rasped. His eyes darted nervously around the group. “I’d given up hope.”

The past week or so, Percy had imagined a lot of scathing things he might say to Nico when they met again, but the guy looked so frail and sad, Percy couldn’t muster much anger.

“You knew about the two camps all along,” Percy said. “You could have told me who I was the first day I arrived at Camp Jupiter, but you didn’t.”

Nico slumped against the helm. “Percy, I’m sorry. I discovered Camp Jupiter last year. My dad led me there, though I wasn’t sure why. He told me the gods had kept the camps separate for centuries and that I couldn’t tell anyone. The time wasn’t right. But he said it would be important for me to know…” He doubled over in a fit of coughing.

Hazel held his shoulders until he could stand again.

“I—I thought Dad meant because of Hazel,” Nico continued. “I’d need a safe place to take her. But now…I think he wanted me to know about both camps so I’d understand how important your quest was, and so I’d search for the Doors of Death.”

The air turned electric—literally, as Jason started throwing off sparks.

“Did you find the doors?” Percy asked.

Nico nodded. “I was a fool. I thought I could go anywhere in the Underworld, but I walked right into Gaea’s trap. I might as well have tried running from a black hole.”

“Um…” Frank chewed his lip. “What kind of black hole are you talking about?”

Nico started to speak, but whatever he needed to say must have been too terrifying. He turned to Hazel.

She put her hand on her brother’s arm. “Nico told me that the Doors of Death have two sides—one in the mortal world, one in the Underworld. The mortal side of the portal is in Greece. It’s heavily guarded by Gaea’s forces. That’s where they brought Nico back into the upper world. Then they transported him to Rome.”

Piper must’ve been nervous, because her cornucopia spit out a cheeseburger. “Where exactly in Greece is this doorway?”

Nico took a rattling breath. “The House of Hades. It’s an underground temple in Epirus. I can mark it on a map, but—but the mortal side of the portal isn’t the problem. In the Underworld, the Doors of Death are in…in…”

A cold pair of hands did the itsy-bitsy spider down Percy’s back.

A black hole. An inescapable part of the Underworld where even Nico di Angelo couldn’t go. Why hadn’t Percy thought of this before? He’d been to the very edge of that place. He still had nightmares about it.

“Tartarus,” he guessed. “The deepest part of the Underworld.”

Nico nodded. “They pulled me into the pit, Percy. The things I saw down there…” His voice broke.

Hazel pursed her lips. “No mortal has ever been to Tartarus,” she explained. “At least, no one has ever gone in and returned alive. It’s the maximum-security prison of Hades, where the old Titans and the other enemies of the gods are bound. It’s where all monsters go when they die on the earth. It’s…well, no one knows exactly what it’s like.”

Her eyes drifted to her brother. The rest of her thought didn’t need to be spoken: No one except Nico.

Hazel handed him his black sword.

Nico leaned on it like it was an old man’s cane. “Now I understand why Hades hasn’t been able to close the doors,” he said. “Even the gods don’t go into Tartarus. Even the god of death, Thanatos himself, wouldn’t go near that place.”

Leo glanced over from the wheel. “So let me guess. We’ll have to go there.”

Nico shook his head. “It’s impossible. I’m the son of Hades, and even I barely survived. Gaea’s forces overwhelmed me instantly. They’re so powerful down there…no demigod would stand a chance. I almost went insane.”

Nico’s eyes looked like shattered glass. Percy wondered sadly if something inside him had broken permanently.

“Then we’ll sail for Epirus,” Percy said. “We’ll just close the gates on this side.”

“I wish it were that easy,” Nico said. “The doors would have to be controlled on both sides to be closed. It’s like a double seal. Maybe, just maybe, all seven of you working together could defeat Gaea’s forces on the mortal side, at the House of Hades. But unless you had a team fighting simultaneously on the Tartarus side, a team powerful enough to defeat a legion of monsters in their home territory—”

“There has to be a way,” Jason said.

Nobody volunteered any brilliant ideas.

Percy thought his stomach was sinking. Then he realized the entire ship was descending toward a big building like a palace.

Annabeth. Nico’s news was so horrible Percy had momentarily forgotten she was still in danger, which made him feel incredibly guilty.

“We’ll figure out the Tartarus problem later,” he said. “Is that the Emmanuel Building?”

Leo nodded. “Bacchus said something about the parking lot in back? Well, there it is. What now?”

Percy remembered his dream of the dark chamber, the evil buzzing voice of the monster called Her Ladyship. He remembered how shaken Annabeth had looked when she’d come back from Fort Sumter after her encounter with the spiders. Percy had begun to suspect what might be down in that shrine…literally, the mother of all spiders. If he was right, and Annabeth had been trapped down there alone with that creature for hours, her leg broken…At this point, he didn’t care if her quest was supposed to be solo or not.

“We have to get her out,” he said.

“Well, yeah,” Leo agreed. “But, uh…”

He looked like he wanted to say, What if we’re too late?

Wisely, he changed tack. “There’s a parking lot in the way.”

Percy looked at Coach Hedge. “Bacchus said something about breaking through. Coach, you still have ammo for those ballistae?”

The satyr grinned like a wild goat. “I thought you’d never ask.”

ANNABETH HAD REACHED HER TERROR LIMIT.

She’d been assaulted by chauvinist ghosts. She’d broken her ankle. She’d been chased across a chasm by an army of spiders. Now, in severe pain, with her ankle wrapped in boards and Bubble Wrap, and carrying no weapon except her dagger, she faced Arachne—a monstrous half-spider who wanted to kill her and make a commemorative tapestry about it.

In the last few hours, Annabeth had shivered, sweated, whimpered, and blinked back so many tears that her body simply gave up on being scared. Her mind said something like, Okay, sorry. I can’t be any more terrified than I already am.

So instead, Annabeth started to think.

The monstrous creature picked her way down from the top of the web-covered statue. She moved from strand to strand, hissing with pleasure, her four eyes glittering in the dark. Either she was not in a hurry, or she was slow.

Annabeth hoped she was slow.

Not that it mattered. Annabeth was in no condition to run, and she didn’t like her chances in combat. Arachne probably weighed several hundred pounds. Those barbed legs were perfect for capturing and killing prey. Besides, Arachne probably had other horrible powers—a poisonous bite, or web-slinging abilities like an Ancient Greek Spider-Man.

No. Combat was not the answer.

That left trickery and brains.

In the old legends, Arachne had gotten into trouble because of pride. She’d bragged about her tapestries being better than Athena’s, which had led to Mount Olympus’s first reality TV punishment program: So You Think You Can Weave Better Than a Goddess? Arachne had lost in a big way.

Annabeth knew something about being prideful. It was her fatal flaw as well. She often had to remind herself that she couldn’t do everything alone. She wasn’t always the best person for every job. Sometimes she got tunnel vision and forgot about what other people needed, even Percy. And she could get easily distracted talking about her favorite projects.

But could she use that weakness against the spider? Maybe if she stalled for time…though she wasn’t sure how stalling would help. Her friends wouldn’t be able to reach her, even if they knew where to go. The cavalry would not be coming. Still, stalling was better than dying.

She tried to keep her expression calm, which wasn’t easy with a broken ankle. She limped toward the nearest tapestry—a cityscape of Ancient Rome.

“Marvelous,” she said. “Tell me about this tapestry.”

Arachne’s lips curled over her mandibles. “Why do you care? You’re about to die.”

“Well, yes,” Annabeth said. “But the way you captured the light is amazing. Did you use real golden thread for the sunbeams?”

The weaving truly was stunning. Annabeth didn’t have to pretend to be impressed.

Arachne allowed herself a smug smile. “No, child. Not gold. I blended the colors, contrasting bright yellow with darker hues. That’s what gives it a three-dimensional effect.”

“Beautiful.” Annabeth’s mind split into two different levels: one carrying on the conversation, the other madly grasping for a scheme to survive. Nothing came to her. Arachne had been beaten only once—by Athena herself, and that had taken godly magic and incredible skill in a weaving contest.

“So…” she said. “Did you see this scene yourself?”

Arachne hissed, her mouth foaming in a not-very-attractive way. “You are trying to delay your death. It won’t work.”

“No, no,” Annabeth insisted. “It just seems a shame that these beautiful tapestries can’t be seen by everyone. They belong in a museum, or…”

“Or what?” Arachne asked.

A crazy idea sprang fully formed from Annabeth’s mind, like her mom jumping out of Zeus’s noggin. But could she make it work?

“Nothing.” She sighed wistfully. “It’s a silly thought. Too bad.”

Arachne scuttled down the statue until she was perched atop the goddess’s shield. Even from that distance, Annabeth could smell the spider’s stink, like an entire bakery full of pastries left to go bad for a month.

“What?” the spider pressed. “What silly thought?”

Annabeth had to force herself not to back away. Broken ankle or no, every nerve in her body pulsed with fear, telling her to get away from the huge spider hovering over her.

“Oh…it’s just that I was put in charge of redesigning Mount Olympus,” she said. “You know, after the Titan War. I’ve completed most of the work, but we need a lot of quality public art. The throne room of the gods, for instance…I was thinking your work would be perfect to display there. The Olympians could finally see how talented you are. As I said, it was a silly thought.”

Arachne’s hairy abdomen quivered. Her four eyes glimmered as if she had a separate thought behind each and was trying to weave them into a coherent web.

“You’re redesigning Mount Olympus,” she said. “My work…in the throne room.”

“Well, other places too,” Annabeth said. “The main pavilion could use several of these. That one with the Greek landscape—the Nine Muses would love that. And I’m sure the other gods would be fighting over your work as well. They’d compete to have your tapestries in their palaces. I guess, aside from Athena, none of the gods has ever seen what you can do?”

Arachne snapped her mandibles. “Hardly. In the old days, Athena tore up all my best work. My tapestries depicted the gods in rather unflattering ways, you see. Your mother didn’t appreciate that.”

“Rather hypocritical,” Annabeth said, “since the gods make fun of each other all the time. I think the trick would be to pit one god against another. Ares, for instance, would love a tapestry making fun of my mother. He’s always resented Athena.”

Arachne’s head tilted at an unnatural angle. “You would work against your own mother?”

“I’m just telling you what Ares would like,” Annabeth said. “And Zeus would love something that made fun of Poseidon. Oh, I’m sure if the Olympians saw your work, they’d realize how amazing you are, and I’d have to broker a bidding war. As for working against my mother, why shouldn’t I? She sent me here to die, didn’t she? The last time I saw her in New York, she basically disowned me.”