The Frozen Sky

1.

Vonnie ran with her eyes shut, chasing the sound of her own boot steps. This channel in the rock was tight enough to reflect every noise back on itself, and she dodged through the space between each rattling echo.

She knew the rock was laced with crevices and pits. She knew she might catch her leg or fall with every step.

But she ran.

She crashed one shoulder against the wall. Impact spun her sideways. She hit the ground hard. Sprawled on the rock, Vonnie pushed herself up and glanced back, forgetting the danger in this simple reflex.

The bloody wet glint in her retinas was only a distraction, a useless blur of heads-up data she couldn’t read.

Worse, her helmet was transmitting sporadically, its side mount and some internals crushed beyond saving. She’d rigged a terahertz pulse that obeyed on/off commands, but her sonar and the camera spot were dead to her, flickering at random — and the spotlight was like a torch in this cold.

Vonnie clapped her glove over the gear block on her helmet, trying to muffle the beam. She wasn’t concerned about the noise of her boot steps. The entire moon groaned with seismic activity, shuddering and cracking, but heat was a give-away. Heat scarred the ice and rock. For her to look back was to increase the odds of leaving a trail.

Stupid. Stupid.

She’d never wanted to fight. Yes, the sunfish were predators. Their small bodies rippled with muscle, speed, and unrelenting aggression, but they were also beautiful in their way. They were fascinating and strange.

Were they smarter than her?

The sunfish had outmaneuvered her twice. More than anything, what Vonnie felt was regret. She could have done better. She should have waited to approach them instead of letting her pride make the decision.

In some ways Alexis Vonderach was still a girl at thirty-six, single, too smart, too good with machines and math to need many friends. She was successful. She was confident. She fit the ESA psych profile to six decimal points.

Now all that was gone. She was down to nerves and guesswork and whatever momentum she could hold onto.

She lurched forward, pawing with one hand along the soft volcanic rock. With her helmet’s ears cranked to maximum gain, each rasping touch of her boots and gloves was a roar. Larger echoes hinted at a gap above her on her left. Could she climb up? Trying to listen for the opening, she turned her head.

Her face struck a jagged outcropping in the wall. Startled, she jerked back. Then her hip banged against a different rock and she fell, safe inside her armor.

Standing was a chore she’d done hundreds of times. She did it again. She kept moving.

Vonnie didn’t think the sunfish could track the alloys of her suit, but they seemed like they were able to smell her footprints. Fresh impacts in the rock and ice left traces of dust and moisture in the air. There was no question that the sunfish were highly attuned to warmth. She’d killed nine of them in a ravine and covered her escape with an excavation charge, losing herself behind the fire and smoke… and they’d followed her easily.

What if she could use that somehow? She might be able to lead them into a trap.

Vonnie was no soldier. She had never trained for violence or even imagined it, except maybe at a few faculty budget meetings. That was an odd flicker of memory. Vonnie clung to it because it was clean and bright. She would have given anything to return to her old life, the frustrations and rewards of teaching, her classroom, and her tidy desk.

She fell once more, off-balance with her hand against her head. A heap of rubble had caught her boots and shins. She scrabbled over what appeared to be a cave-in. The noises she made were loud, clattering booms — but the echoes stretched at least ten meters above her, defining a tall chasm.

I can pin them here, she thought.

If she burned the rock and left a false trail, she could drop the rest of the broken wall on them when they passed. Then they would give up. Didn’t they have to give up? After the bloodbath in the ravine, she’d killed two more in the ice, and others had been wounded. Could the sunfish really keep soaking up casualties like that?

Vonnie could only guess at their psychology. Although she was blind, she knew of the existence of light. Although she was alone, she believed someone would find her.

She thought the history of this race was without hope. The sunfish had a phenomenal will to live, but the concept of hope required a sense of future. It required the idea of somewhere to go.

The sunfish had never imagined the stars, much less reached up to escape this black, fractured world.

This damned world.

No less than four Earth agencies had landed mecha on the surface to strip its resources. Then they’d sent a joint team in the name of science, handpicking three experts from China, America, and Europe — and Bauman and Lam had both died before First Contact, crushed in a rock swell. Would it have made any difference?

The question was too big for her. That the sunfish existed at all was a shock. Humanity had long since found Mars and Venus stillborn and barren. After more than a century and a half, the SETI radioscopes hadn’t detected any hint of another thinking race within a hundred and fifty lightyears of Earth.

Looking so far away was like a bad joke. The sunfish had been inside the solar system for millennia, a neighbor and a counterpart. It should have been the luckiest miracle. It should have been like coming home, but that had been Vonnie’s worst mistake: to think of the sunfish as similar to human beings. They were a species that seemed to lack fear or even hesitation, which might be exactly why her trap would work.

She decided to risk it. She was exhausted and hurt. If she stopped running, she would have time to attempt repairs and regain the advantage.

I hope they don’t come, she thought.

But she found a small shelf in the cliff above the rock slide, then settled in to kill more of them.

2.

Jupiter’s sixth moon was an ocean, a deep, complete sphere too far from the sun to exist as liquid on its surface — not at temperatures of -162° Celsius. Europa was cocooned in ice. The solid crust ran as thick as twenty kilometers in some regions, which meant that for all intents and purposes, it enveloped Europa like a single continent

Human beings first walked the ice in 2094, and flybys and probes had buzzed this distant white orb since 1979. Europa was an interesting place.

For one thing, it was as large as Earth’s moon — nearly as large as Mercury — which meant it could have been a planet in its own right if it orbited the sun instead of Jupiter. It also had a unique if extremely thin oxygen atmosphere caused by the disassociation of molecules from its surface. It was water ice.

It was a natural fuel depot for fusion ships.

Before the end of the twenty-first century, the investment of fifty mecha and two dozen more in spare parts was well worth an endless supply of deuterium at the edge of human civilization. The diggers and the processing stations were fusion-powered, too. So were the tankers parked in orbit.

Spacecraft came next, some with crews, some piloted by robots, and eighteen years passed.

That quiet period might have been much longer. The mecha were on the equator, where it was easiest for the tankers to hold position above them without constantly burning fuel, fighting Jupiter’s gravity and the tug of other moons — but Jupiter’s mass created other conflicts.

Deep inside Europa, its rocky core flexed, generating heat and volcanic activity. The ocean rolled with murderous tides. On the surface, the ice suffered its own turmoil, creating different environments such as “canyons,” “melts,” “domes,” and “chaos terrain.” Especially on the equator, the ice bulged and sank and turned over on itself.

Only the smoother, so-called “plains” were deemed safe by the men and women who guided the mecha by remote telepresence. Looking ahead, they sent rovers in all directions, surveying, sampling.

At the southern pole was a smooth area that covered nearly thirty square kilometers.

Many rovers went there.

3.

Vonnie shivered, an intensely ugly sensation inside her suit. She’d locked the joints and torso to become a statue, preventing herself from causing any movement whatsoever, and yet inside it she was skin and muscle.

The feel of her body against this shell was repulsive. She squirmed again and again, trying to shrink away from it, which was impossible.

The rut in her thinking wasn’t much better. She wished Choh Lam hadn’t tried to… She wished somehow she’d saved the rest of her crew. Lam understood so much so fast, he might have already found a way out, a way up.

She’d cobbled together a ghost using his mem files, but she couldn’t give it enough capacity to correct its flaws. In order to expand the ghost’s abilities, she would need to shut down her ears or the override she’d programmed into her heat exchanger, each a different kind of death. If she couldn’t hear, she would be utterly lost. And if her suit exuded body heat instead of storing it, her ambush would fail.

It would be better to forget Lam. She thought she should erase him, but even at three-quarters logic he was useful. He’d suggested a tranquilizer and Vonnie had popped one tab, which slowed her down enough to feel clear again. Clear and cold. She shouldn’t be cold, sweating inside her hard shell, but the waiting was like its own labyrinth of ice — the waiting and the listening and the deep bruises in her face.

She didn’t care how sophisticated the medical systems were supposed to be. On some level, her body knew it was hurt, even numbed and shot full of don’t-worry.

Her head had a dozen reasons why she was safe, but her body knew the sunfish would come again. The lonely dark was alive. That truth no longer surprised her, and she strained her senses out into the dark, frozen spaces of the chasm below her.

She was more afraid of missing the sunfish than of drawing in an attack. It was superstitious to imagine they could hear her thoughts, she knew that, but at the ravine they’d run straight to her hiding place despite three decoys. How did they keep zeroing in on her?

She needed to learn if she was going to live.

This rock shelf seemed defensible. There was nowhere to retreat but she only had one approach to cover. Overhead was a spongework of holes where she could dump her waste heat before leaving.

Vonnie laid on her belly, facing outward, trying to eat and trying to rest, trying to ignore the nasty, anesthetized pressure of the med beetles slithering in and out of her temple, her cheek, and her eye socket.

Both eyes were damaged, yet she’d elected to deal with her left eye first in case something went wrong. The nanotech might need to scavenge one eye to save the other. Step by step surgeries had been Lam’s idea. He’d also agreed that her helmet would retain its integrity if she broke off her gear block and stripped it for parts. What else would he have tried?

The plastisteel of her suit should contain all sound, but there was another risk in talking, a risk she ignored just to be with someone.

“Are you still there?” she whispered.

His voice was uneven and rushed, too emotional for an artificial intelligence:

—Von, listen. Don’t close me down again, please.

“Tell me what Lam would do,” she said. “Am I safe here? I need to rest. I laid down a false trail with my spotlight.”

—They’ll catch us.

“Did you check my map? I made it almost three klicks.”

—They will. The probability is eighty-plus percent, but I can talk to them. We have enough data now. With temporary control of the suit, I could at least establish…

“No.”

—Vonnie, most of their language is postures and shapes. I can’t tell you fast enough how to move.

“No. Self-scan and correct.”

—Von, wait.

“I said scan for glitches and correct. Off.”

Could a ghost be crazy? If so, it was her fault. Lam was the first she’d ever made. She’d rushed the process because she was angry with him — the real him. She’d let him remember how he died, and it had made him erratic. Maybe he’d never doubted himself before.

Bauman would have been a better friend. Bauman had been older, calmer, another woman, but she was a geneticist and Lam’s biology/ecology skills were too valuable. The decision had been obvious. Vonnie didn’t have the resources to pull them apart, then build an overlay with Bauman’s personality and Lam’s education.

She was alone.

She itched her fingertips inside her rigid glove. Too soon, she prompted her clock and was discouraged. It would be six minutes until her skull was repaired, thirty before she regained her optic nerve.

Can I improve him? she wondered. I can’t give him more capacity, but maybe I can talk him through his error lists. He’s a learning system. He should respond.

Patience was supposed to be one of her strengths. Four years ago, she’d been a top instructor at Arianespace. She’d led classes in cybernetics, although her specialty had been ROM welding and construction, using remote operated mecha in low gravity environments, zero gravity, underground, or underwater. Then she’d been recruited by the European Space Agency for the same job with better pay and better students.

Vonnie enjoyed working with her hands. She loved igniting a spark in people who wanted to learn. Tailoring her approach for each new individual kept her job interesting. The ESA was full of ambitious, hyper-educated men and women who challenged her with their egos, their experience, and their own expectations.

“You can’t wait until you can see,” she argued with herself. “Otherwise he’ll keep trying to take over the suit. Run more voice checks. Keep command. If he gets twitchy, just lock him down again.”

A noise echoed through the blackness like two rocks clacking together, barely audible in the distance.

On my left, she thought.

Was it a rock fall? Tremors and avalanches regularly split these caverns. The noise could have been a natural event, but Vonnie knew better.

Something was coming.

4.

Europa’s volcanoes added to the unrest in the ice. Below many of the “dome” and “melt” environments, subsurface peaks of lava had proved common, elongated fins and spindles that could not have existed if this moon had more than a thirteenth of Earth’s gravity. The movements in the ice eroded the rock, then distributed it everywhere.

Rock was a problem for the mecha. It damaged blades and claws. It jammed in pipes. Even dust would make a site unattractive, and ESA Rover 011 was quick to give up on a wide area of the southern plain when it brought up contaminants in its drill cylinder.

But the rover was well-engineered. Belatedly, it noticed the consistency of shape among the debris. Then its telemetry jumped as it linked with a tanker overhead, using the ship’s brain to analyze the smattering of solids.

Finally the rover moved again, sacrificing two forearms and a spine flexor to embrace its prize, insulating the sample against the near-vacuum on Europa’s surface.

Impossible as this seemed, given the preposterous cold and the depth from which the sample came, the contaminants were organic lifeforms, long dead, long preserved: tiny, albino bugs with no more nervous system than an earthworm.

5.

Vonnie opened her blind eyes to nothing and her ears were empty, too — but she was sure. Something was coming. Inside the rigid shell of her suit, she moved but could not move, a surge of adrenaline that had no release.

Trembling, she waited. Brooding, she cursed herself. She’d spent her life making order of things, and she couldn’t get her head quiet. She made everything familiar by worrying through the mechanics of her trap again and again.

She’d snapped her next-to-last excavation charge in two and rigged a second detonator, setting one charge in the ceiling beyond her rock shelf, the other below and to her left. The blasts would shove forward and down, although in this gravity, she could expect ricochets and blowback.

Good.

The sunfish fought like a handful of rubber balls slammed down against the floor, spreading in an instant, closing on her from every angle. Their group coordination was beyond belief. To a species whose perceptions were based on touch and sonar, language consisted of gesture and stance. They always knew each other’s mood and seemed to share it like a flock of birds.

Without her eyes, their synchronized attacks were an even greater threat. Her terahertz pulse was better at sounding out large, immobile shapes than at following objects in motion. Vonnie knew she would lose track of some of them, so she’d smash everything within fifty meters.

Her armor could sustain indirect hits from the porous lava rock. She planned to bait them, bring them close, then roll into a crevice behind her and hit the explosives, after which she would slash any survivors with her laser.

It was a cutting tool, unfortunately, weak at the distance of a meter. Worse, if she overheated the gun, she would probably not be able to repair it. Her nanotech was limited to organic internals. Most of the tool kits on her waist and left hip had been torn away.

“Stop thinking. Damn it, stop talking,” she murmured, the words as rapid as her heartbeat.

Just stop it.

Could they really hear her mind? She’d studied the sunfish with the acute concentration of a woman who might never see anything else again, and with all the skills of a teacher evaluating her newest class.

The sunfish definitely had an extra sense, maybe the ability to… feel weight or density. That would serve them well in the ice. So they would be able to differentiate her from the environment.

For once, she wanted them to find her. Vonnie reactivated her suit and rose into a crouch, strobing the chasm below with a terahertz pulse. She thought her signals were outside the sunfishes’ range of hearing, but she’d revealed herself as soon as her armor scraped against the rock.

Nothing. There was nothing.

“Oh God.” She choked back the sound and swept the bent spaces of the chasm, quickly locating pockets in the ceiling that she hadn’t anticipated and couldn’t reach with her signals. The angle was too steep. Using her terahertz pulse was like turning on a light in what she thought was a closet and finding instead that half of the house was gone — and her enemy needed only the thinnest openings to surround her.

Were they already too close? She’d seen it before, a dozen sunfish upside down on the rock like fat creeping muscles.

Vonnie aimed her laser at the ceiling even as she groped with her other hand for a chunk of rock. There was gravel, too, and a head-sized boulder. She’d gathered every loose piece of lava she could find.

Should she throw it now? Try to provoke them? Her thumb gritted in the rock as she clenched her fist.

She was a decent shot with a ball. She’d grown up with three younger brothers. But the suit itself was a weapon. The suit had low-level AI programs that could make her something like a passenger inside a robot. There were voice menus designed for activities like climbing or welding because human beings got tired. The suit did not. It also had radar targeting that she could not see, and it would limit the velocity of its throws only to avoid damaging her shoulder and back.

She didn’t trust it.

She’d used most of her AI programs to hold an imprint of her ghost. The suit was rotten with Lam’s mem files. Twice the ghost had caused interrupts, trying to reconfigure itself, trying to seize control, and yet Vonnie was afraid to purge him. Deleting his mem files might affect her suit’s amplified speed and brawn.

“Are you still there?” she hissed.

—Von, listen. Don’t close me down again, please.

That was the same thing it always said. God. Oh God. She didn’t have time to hassle with him.

“Combat menu,” she said.

—Online.

She hesitated. Right now, the ghost was somewhat contained. That would change if she gave it access to defense modes. Doing so was a bad gamble. The extra capacity might be precisely what the ghost needed to self-correct… or the stupid, miserable AI might corrupt the most basic functions of her suit. Was there any other way?

“I need auto-targeting only,” she said. “Fire by voice command.”

—Von, that drops efficiency to thirty percent.

“Fire by voice command. Confirm.”

—Listen to me.

Four slender arms reached out of the ceiling.

6.

It was easy to be friends with Choh Lam. In his mid-thirties, skinny and short, with big ears, he made a point of being nonthreatening. He was freak smart but also soft-spoken, hiding himself in a kind voice, both eager and shy. He probably didn’t realize he had restless eyes because in every other way he moved like he talked, gently.

Vonnie’s impression was of a man who’d spent his life holding back. He was a man who wanted to belong.

Lam made his break with that kind of thinking before the boards agreed how many people to send to Europa. Even before the mining groups had reprogrammed their mecha for new, more intensive searches, Lam let his genius show and posted a sim that guaranteed his slot on the mission — for bugs. Just bugs. That was all the ESA rover had found. No one believed this ice ball could support much else, and yet there were fifteen thousand volunteers in the first week.

Fifteen thousand experts wanted to abandon their families and their homes despite knowing that the trip out to Europa would be two and a half months cramped inside a hab module; that the food would be slop-in-a-bag; that Jupiter seethed with radiation.

In the virtual meetings for candidates, Vonnie had grinned at the enthusiasm they shared. Homo sapiens’ best traits were heart and curiosity. Despite all of their technology, despite developing spaceflight, AI, and nano medicine, there was still so much of the ape in them.

Fifteen thousand people suddenly didn’t care about anything except getting their feet on the ice and grubbing around for exotic life. It was a riddle unlike anything else.

Where did the bugs come from?

The weak little creatures weren’t burrowers, not with their spherical body shape and dorsal whiskers. Also, there were variations in the ice. The narrow layer containing the bugs was nowhere near as old as the rest of the sample, and loaded with chlorides and minerals.

Europa possessed every building block of life. There was water, heat, and organic material from comet and meteor strikes. They had long speculated that Europa’s great ocean was not wholly frozen. The icy crust went down an average of ten kilometers, reaching twenty km in places, but beneath it was slush and eventually liquid. In fact, some areas would be as hot as boiling where raw magma or gas pushed up from the moon’s rocky core.

Was there also life in the ocean? If yes, it must be limited to hardy bacteria like those found near ocean-floor volcanoes on Earth or in the corrosive toxins of mine tailing ponds. Europa’s surface was stained with sulfuric acid and salt. This was evidence of caustic pH levels in the ocean.

Lam’s school of thought predicted a world inside the ice, a small, unsteady, vertical world. A hundred man-made probes had found nothing for a hundred years, but Lam said that was to be expected. He drew his model in an area where a fin of subsurface mountains partly diverted the crushing, glacial tides. The safe zone was a mere fifteen cubic kilometers in volume — and even within its confines, the ice and rock were burned and torn.

Lam was among the first to understand the violence of this environment. It mesmerized him.

Here are the bugs in an open rift, he said. What are they doing? We don’t know. Mating? Migrating? Nearby there is a rumble, and a super-heated geyser floods the rift. It collapses, then gradually freezes with the bugs suspended inside. But there are more pocket ecologies stacked throughout the region, some with tenuous atmospheres of water vapor or volcanic gases such as nitrogen and carbon dioxide, poisonous hydrogen chloride, and explosive hydrogen sulfide.

The warm holes in the ice were mild compared to the acidic salt ocean. Eons ago, in some of these crannies, bacteria had grown and thrived. The same crude microorganisms had been the first lifeforms to inhabit Earth. They were called chemoautotrophs — self-nourishing chemical reactions that ate iron, sulfur, ammonia, or manganese.

The bacteria refused to die.

In time, isolated from the minerals and poisons that fed them, a few strains had adapted to split water molecules as a new energy source, eating hydrogen instead of iron or manganese. The byproduct was oxygen.

The new bacteria released oxygen gas into some of the pocket ecologies. Oxygen changed things forever. It allowed for larger, faster, more complex organisms. Life on Europa flourished because it had no other choice, evolving and spreading never more than a few steps ahead of constant upheaval.

7.

Christmas Bauman was fifty-three and not so new to long-term commitments. That was partly why she won her slot as the expedition commander, as a balance to Lam and Vonderach. Vonnie liked her, too. Bauman pretended sarcasm with them, but it was a way of communicating her experience. Vonnie could measure Bauman’s amusement in each fraction of a centimeter that her brows lifted above her muddy green eyes.

She was heavier in the chest and hips than Vonnie and more willing to use her body despite her age, dominating conversations by wading into the middle of any group.

She had her own fascination. “What if—” she kept saying.

What if the bugs weren’t dead? They might be hibernating or otherwise biologically active. What if their chemistry wasn’t too strange to co-opt, and could be used in geriatrics or cryo surgery? Yes, they appeared to have been scalded in magma-heated water and then gradually mashed and distorted by the freezing process. The bugs appeared very dead indeed, but who could say what adaptations were normal on Europa? Maybe they’d evolved to spread in this manner, like spores, preserved for ages until the ice opened up again. No one could be certain until a gene smith examined the bugs, so Bauman committed to a year’s hardship on nothing more than spectral scans and what if.

They made a game of it inside the weightless cage of their ship, What if I trade you my dessert tonight for some of your computer time? and What if you turn off your friggin music?

The three of them spent eleven weeks in that box. There wouldn’t have been room for them to start bouncing off the walls, and Christmas Bauman stepped into her role very naturally as their leader — a little bit of a mom, a little bit of a flirt.

Bauman kept the pressure low with her jokes and also made sure they paid attention to each other, because the temptation was to look ahead. Lam constantly updated his sims as the mecha sent new data. Vonnie had responsibility for ships’ systems and maintenance. All three of them reviewed and participated in various consultations, boards, and debates.

Eleven weeks. It could have been long enough to learn to despise each other or even short enough to remain strangers until they arrived, but Bauman set aside much of her own work to invest in her colleagues instead.

They were eighteen days from Europa when the mecha found carvings in the ice.

This time it was a Chinese rover, running close to the ESA find. Its transmissions were encrypted and altercast, but the Europeans and the Brazilians each caught enough of the signal to have something to work with. In less than four hours, the naked code went systemwide.

Vonnie had learned politics at the University of Stuttgart, and, later, as an instructor at Arianespace. Information was power. There didn’t seem to be much sense in withholding the discovery. Too many eyes were watching. Most likely, the Chinese had protected their discovery out of habit and would have shared it within a day or two. Nonetheless, the mood on Earth took a hit. Vonnie and Bauman both received priority messages listing new contingencies and protocols.

The tension could have ruined them. They could have sunk their energy into the worst kind of distraction, yet Bauman saw them through.

“What if he is a dastardly chink spy?” she asked straight-faced.

Vonnie gaped at her, embarrassed by the slur.

Lam laughed out loud. “Yankee scum,” he said to Bauman, who added, “Hey, let’s not leave her out of this. What do you think, Von? I guess that makes you the Aryan superwoman.”

“Right.” Vonnie touched her blond hair, so much lighter than Lam’s jet black stubble or Bauman’s sand-colored mop. She didn’t like having their attention drawn to her best feature, which she’d cropped into a buzz cut to keep it out of her face in zero gee.

Aryan wasn’t the loaded word it had been for Vonnie’s great-great-great-grandparents, but with Germany leading the European Union again, their nation remained self-conscious about its sins in World War II. More recently, they’d seen two generations of conflict with immigrants drawn to Germany’s riches. Some political parties had walked a slippery line between racism and protecting their culture, drawing condemnation from people all over the globe. Vonnie certainly looked the part of Hitler’s master race, fair-skinned, blue-eyed, trim and fit. To her, that meant she’d had to work harder than most candidates to prove herself.

“We know we’re good people even if she’s gorgeous, you’re too smart, and I’m overbearing,” Bauman said.

Vonnie and Lam nodded. They were friends enough to realize they were on their own, no matter what played out back home. Inside the ship’s hab module, they gathered around a display to watch their datastreams.

The telemetry stolen from the Chinese rover was in radar and infrared. It showed the rover’s low-slung perspective trundling forward with gradients of temperature laid over white-and-green imagery. To its left, irregular lumps masked the horizon where warm gas oozed from several vents. The rover turned closer— And the perspective fell sideways.

In front of the camera, six meters of ice bulged. Gas spewed upward. There was pelting hail. Then the blow-out was over, revealing a trench in the ice. Its roof had thinned with age. Otherwise the rover might have crossed safely, never marking this hollow as anything except another frigid, empty branch of an inactive vent. Instead, the rover extended a wire probe down into the shadows, confirming a glimpse of repetitive shapes molded from the ice.

In radar, the carvings were stark, extraordinary artifacts.

“What if everything down there was killed when the air went out?” Vonnie asked, thinking like an engineer, but Bauman said, “No, this trench is abandoned. It’s isolated. ”

“She’s right,” Lam agreed.

Vonnie smiled, glad for their excitement. Then she saw Lam’s face and frowned, feeling one step behind.

“Look,” he said as he ducked his eyes in disappointment.

“This is good, isn’t it?” Vonnie said. “There’s no way the bugs cut those patterns in the ice. That means there’s something else on Europa — something bigger.”

“Yes.” But he was unhappy.

Puzzled, Vonnie turned back to the display, trying to see what Lam had seen.

The carvings repeated one shape over and over in eight vertical columns of four apiece, a form much like an eight-pointed star. From tip to tip, each symbol measured 1.2 meters wide. Each one was set deep enough in the ice that it was half a meter thick through its middle, like small domes with tapered limbs.

Every arm was knuckled and bent seemingly at random. Vonnie thought the carvings could be a sun calendar. She started to say so, then stopped herself.

Jupiter was five times farther from the sun than Earth. Their star would look like a compact spark in Europa’s sky. Because its atmosphere was nonexistent compared to Earth’s, with no clouds or moisture to deflect sunlight, Europa’s surface would actually appear brighter than a summer day in Germany… and yet she’d soaked up enough biology from Lam to realize there had never been anything walking on top of the ice.

Is he mad at what people are saying? she wondered.

The first theories from Earth dismissed the carvings as the result of hive behavior by the bugs. They cited termite mounds, ant mounds, spider pits, and even the mud nests of cliff swallows.

The math in the carvings implied something more. Eight times four times eight looked like a pattern that had been done on purpose, but many insects on Earth created symmetrical designs. Some biologists proposed the carvings were territorial markings or an attempt to reinforce the tunnel wall with interlocking shapes. A species whose existence depended upon the ice could have developed construction techniques like gophers or ants. The symmetry might be incidental.

No one was ready to go on record that the carvings were a written language, although efforts to translate the wall were percolating on the net. Early human civilizations had used repetitive symbols such as cuneiform and hieroglyphics before developing alphabets. Some people insisted the carvings held a message. There were too many exact, subtle alignments among the sun-shapes’ two hundred and fifty-six arms.

Regardless, the growing consensus was that the carvings demonstrated at least chimpanzee-equivalent intelligence.

“Why are you upset?” Vonnie asked.

“Because we missed them,” Lam said. “We’re too late.”

“There could be inhabited chambers nearby. You don’t know what’s down there.”

Lam shook his head, scrolling through their displays. “The trench is older than you think,” he said. “Too old. Look at the drift.”

The three columns furthest to the east side appeared sloppy, as if they’d been carved in a hurry, but that was because the ice had swelled, deforming the trench — and in this safe zone, the surface tides could be measured in millimeters per century.

Vonnie felt a weird quiver down her spine. Were the carvings actually words? If so, the message was more ancient than the dim, half-forgotten histories recorded in the Bible.

“Cheer up,” Bauman said. “Even if we don’t find anything except bones, this will be the greatest archeological dig of all time.”

“We’ll be on the cover of every ’zine in the system,” Vonnie said, trying to make Lam smile, but he only grimaced and looked away.

“Whoever made those carvings has been dead for ten thousand years,” he said.

8.

Vonnie landed their slowboat on Europa a week before the new high-gee launches would arrive, each carrying new teams of eight to twenty-four people sent by the Brazilians, the Chinese, NASA, and the ESA.

Seven days should have been enough for Vonnie, Bauman, and Lam to begin exploring the site. Wire probes had confirmed that one end of the trench slumped deep into the ice, becoming a tunnel. It crooked sideways and down before shrinking into a series of pockets and holes too dense for their radar arrays to penetrate. For all anyone knew, there were more carvings farther down, but they were directed to wait. The larger ships carried many of the experts who hadn’t been picked the first time. Also included were a number of bureaucrats.

There was no question that this crowd would be better able to process the trench, so Vonnie and Bauman spent their time prepping gear and fielding media requests while Lam hid away with his data.

They were celebrities. For an engineer and a gene smith, playing at being popular was a fun diversion. Vonnie showed off their non-proprietary hardware and public maps of the ice while Bauman talked about the sexier aspects of gene splicing like metabolic chargers. Together they were worth a sixty-second update every day on the same news feeds that had rarely mentioned their mission during the long, tedious journey to Europa. Now they were a hot pick — girl explorers on an alien moon — and the ESA and NASA administrators allowed them to say almost anything. Both women were jubilant and loud. It was topnotch media.

Meanwhile, Lam smoldered. “You see what’s happening,” he said one day before breakfast, standing with his back to the hab module window as if testing himself.

Vonnie couldn’t leave the viewport alone. Bauman constantly made her wipe off her fingerprints. Outside, their mecha wandered across the frozen plain, glinting in the vivid, reflected glow of Jupiter. “I know it’s tough to wait,” Vonnie said without looking at him.

“You sound just like them,” he said.

“Hey, easy. I’m on your side.”

“You think I’m worried because they might grab some of the glory? Because I had to live in a box with two attractive women for eleven weeks?”

Vonnie turned at attractive, feeling a little wary. So far, Lam had been scrupulous about keeping his distance.

“You’ve seen their org chart,” he said. “Who do you think’s in charge, the people like you and me?” His brown eyes searched her face, then shifted to the viewport behind her. “It’s being politicized,” he said. “The fuel. The water. You have to listen to what they’re really saying.”

The ice. A few Earth governments had called for an end to the mining. Others had too much invested in their colonies and fleets to shut down their supplies of deuterium, hydrogen, and bulk water. Away from the pole, the mining continued. Even now, a PSSC robot ship was carefully unfolding in orbit. The mecha it carried had been funded years ago and the ship had been in transit for months. That kind of inertia was fundamental to nearly every aspect of modern civilization.

The ice. Normal water held no more than .015% deuterium, but the precious gas could be separated, compressed and pumped into containers, then lobbed out of Europa’s weak gravity. The tankers filled faster than they could be built, and escaping Jupiter wasn’t expensive, diving in close and slinging away. The old god was well-positioned to feed the inner planets. In recent years, some of the catapults on Europa’s surface had begun hurling containers equipped with nothing more than radio beacons into slow, sunward trajectories. If those containers didn’t arrive for years, even if one or two went missing, no problem, they were lined up like an endless supply train and as cheap as dirt.

The ice. Deuterium-deuterium fusion reactors kept people alive on Luna and Mars and everywhere in between. Water/oxygen futures had become more valuable than gold. The solar system was in bloom. The Chinese had expanded with total commitment, and other nations were growing as fast as possible to keep from being left behind.

“They’ve already given up on most of Europa,” Lam said. “It’s too easy. They’ve been tearing it apart for twenty years without finding anything. I even helped them. They’re all posting my sim like it’s proof — like this safe zone is the only one. SecGen Harada will make sure the expedition doesn’t find anything she doesn’t want us to find.”

The Japanese minister had been born in space, and represented six thousand colonists who made up a crucial part of the Earth-orbit economy.

“What do you want to do?” Vonnie said.

“We’ve got a little time, long enough to post so much data they can’t bury it,” Lam said. “You know what I mean. If we wait now, they’ll come up with rationales to keep waiting. First we’ll run more surveys. Then we’ll practice safety plans. Maybe they’ll send in a few crawlers. Meanwhile five or six months go by, and they’ll downplay the whole thing.”

“What do you want to do, Lam?”

“I want to go in.”

It was a career move they’d only make once. They would either be heroes or subject to a great many lawsuits, probably jail time in Lam’s case. Vonnie suspected he’d ask for political asylum. The carvings meant that much to him, more than seeing his family again, more than his apartment in Hong Kong — and for all the right reasons.

Lam wanted to save this world. He wanted proof of the diversity of life implied by the carvings and the complex food chain that must support the carvers.

There would be little or no fossil record inside the ice. At best, the tides would hold a churned-up mishmash of species carried far from their time and habitats, but that was the point. There could be priceless information everywhere. There might be life in other regions.

He accepted that the mining would never stop. Humankind’s appetites were larger than any group of protestors or indignant scientists, but the mining could be restricted. They could be more diligent.

Bauman only argued for a day. She was too much like Vonnie and Lam. Otherwise she wouldn’t have come to Europa. It didn’t help that the men on the radio talked like slaps in the face. They were terse and controlling. Bauman didn’t appreciate their arrogance. She asked Lam to concoct a sim that showed the carvings were in danger, which wasn’t untruthful. The mecha had resealed the trench with steel, glue, and tents, but the carvings were still reacting to near-vacuum. Who could say what data was being lost as the ice broiled?

Forty-eight hours later, they were given permission to enter the trench — only the trench — and Lam laughed and ran for his armor.

“Game over,” he said. “Game over. Once we’re inside, we’ll need to keep poking around, right?”

“Hold on.” Vonnie hugged them both, starting with Bauman. She blushed a little as she approached Lam. “I wanted to… You can’t feel anything in a scout suit,” she explained, and he smiled, touching her hip. Maybe it was the promise of the beginning of something more.

Each set of armor weighed two hundred and twenty kilos. Suiting up required mecha assists. First they took off their clothes. Vonnie blushed again as Lam averted his eyes. Robotic arms painted her temples, throat, wrists, and thighs with nanocircuitry. Then she climbed into the open shell of her suit. She slipped her legs in, connected the sanitary features, and extended her arms into its sleeves.

The assist lowered her helmet over her face. Her armor folded shut. Thousands of needles — some invisible, some as long as four centimeters — sank into her nerves and veins. It didn’t hurt except for the cortical jack. There was a dull, gritting pain. She was online.

Bauman and Lam repeated the process.

Data/comm showed all systems go, but they visually inspected each other’s seals and collar assemblies. They also triple-checked life support. They intended to wear their suits for a six hour shift, but no one left a ship without carrying the maximum load, which was twelve hours of oxygen and five days of food.

In space, astronauts could lug extra cylinders of compressed oxygen or run air hoses from their ship. Inside the trench, there wouldn’t be room for bulky packs or hoses.

As the crew member tasked with their well-being, Vonnie wanted a large safety margin. During training, she’d once spent an uncomfortable thirty-six hour period in her suit, mastering several tricks to recharge her air supply, swapping new cylinders into her pack by herself, adapting nonstandard hoses, changing out filters clogged with smoke or fluid. They prepared for emergencies. She would bring spare cylinders into the trench, although after a single day, even fresh oxygen could not dispel the stink of sweat. In polite company, astronauts called it living with yourself. In cruder terms, the joke went eat yourself. The suit became a toilet. More important, they had no practical limitations on power. Each set of armor contained a plutonium rod which would drive it for decades.

Vonnie walked into the air lock first. The lock was big enough to hold three people in an emergency if they crammed together, but one at a time was more comfortable, so she had a few moments alone.

As she waited outside, she looked across the brittle plain unassisted by her visor. Human perceptions were self-deceiving in this environment, yet she wanted a personal connection. She wanted to try.

The curvature of the moon was noticeably wrong. The horizon seemed too small, too near, while the sun suffered its own fun house effect. It was too far away, yet too bright. The ice glistened and winked. Vonnie had the feeling of standing in a mirage. Leaning blocks of ice jutted from the surface to the northeast. Aside from this ridge, there were no points of reference, only the eerie plain dwindling into blackness and the unfathomable, looming face of Jupiter.

Europa was exotic and alluring — but slowly, a chill filled her mind. The amazement she felt became a vague fear like a premonition.

Her visor was synthetic diamond. Five centimeters thick, it could withstand small arms fire and seventy standard atmospheres of pressure. Fitted with transparent circuitry, a suit’s visor was also designed to shield its wearer from the desolation of space by swaddling her in data. Without those displays, death felt very close. It engulfed her. Vonnie was only safe because of her helmet, gloves, and armor, so she distracted herself with the superhuman abilities of her suit.

“Lights up,” she said. “Grid One. Radar active. Mecha team alpha to me.”

Lam and Bauman emerged from the ship as Vonnie organized her squad of machines — two small burrowers like meter-long centipedes — a stout digger shaped like a wheeled spider bristling with tools, cameras, and arms — and seven relays and beacons ranging in size from a fist to a soccer ball.

Blazing with cameras and spotlights, they approached the long tent erected above the trench, where other machines had prepped two additional plastic bubbles. The three people entered the nearest bubble without the mecha.

“Stage one, go,” Vonnie said.

Her visor darkened as UV lights scoured their armor, baking off every Earth smell and microbe. Next they were sandblasted with melted ice mixed with a dusting of native rock. Fans cooled the exterior of their suits to -160° Celsius, the ambient temperature

When they emerged, they approached the second bubble, which served as an air lock. They entered. The mecha thronged around their feet. Vonnie skimmed through her checklists with an up-and-down motion of her eyes. A sophisticated response program watched her retinal movements as she studied her display, allowing her eyes to dance like fingertips through its menus.

“Stage two, go.”

The mecha peeled back a steel panel, revealing the trench beneath, where they’d constructed a flex ladder. The spotlights died and their radar shut off. Their visors reverted to a 3-D map taken by wire probe, showing old readings as if these were live images. The map was enough for Vonnie to lead her friends and the mecha down to the carvings.

Lam and Bauman bickered contentedly. “I’d like to switch back to radar,” he said.

“Not a chance,” Bauman said.

“At least let me use X-ray.”

“Absolutely not,” Bauman said. “We’ll be as noninvasive as possible. That was the deal.”

Vonnie grinned and looked around. In the bevy of people and mecha, they began to generate new signals to avoid crashing into each other and to examine the carvings, but they limited themselves to sonar to keep from burning the ice with photons or electromagnetic radiation.

For Lam, this was torture. For Vonnie, it was magnificent. Their visors modified their sonar feedback into holo imagery as real as life, and the trench was richly, overwhelmingly textured: an irregular quilt of dewdrops, smooth spots, swells, and depressions. Only the carvings held a pattern.

But why here? she thought.

The trench seemed to be the upper end of a vent, which made the symbols even more intriguing. Why invest such effort marking the walls of what must be a low-traffic area?

Could this be some sort of holy ground? Maybe the carvers had come to the top of their world to pray, although Vonnie knew Lam would contend that any notions of religion were anthropomorphic. Projecting human motives onto things that weren’t human was a natural function of human thinking. It was a fallacy. They had to be careful how they interpreted things.

Vonnie supposed this open space had been a thoroughfare hundreds of years ago. The mecha had detected gaps in the ice where the trench might have branched downward on both sides until the tides squeezed it shut on one end, turning what had been a horseshoe-shaped passageway into a single, straggling tunnel.

Europa had zero axial tilt and was tidally locked, which meant it always showed the same face to Jupiter like Earth’s moon always showed the same side to its planet. On Europa, unfortunately, the consequences were dire. Their models suggested the tidal locking was imperfect.

It was only Europa’s icy crust that showed the same face to Jupiter. Its ocean and its rocky core spun at different rates, and there were no continents to impede the water. Especially on the equator, the hellish, spiraling currents distended the ice. At its poles, Europa was its calmest. Yet even in these quiet pockets, the crust heaved and split.

What had the carvers been doing at the surface? It didn’t make sense. Living here would have been risky, almost suicidal, Vonnie thought. But they came anyway.

Behind her, Lam was uncharacteristically loud, although he tried to soften his words with Bauman’s new nickname. “Look, Yankee, you’ll never pack up the carvings and put them in a museum,” he said. “We’re damaging the wall just by standing here.”

“All the more reason to be noninvasive,” Bauman said. “We don’t know how finely detailed the top layer may be.”

“We’ll get it in one full spectrum burst.”

“We don’t have enough sensors.”

“Vonnie can rig more cameras and mecha.”

“The heat will—”

Another voice intruded. “Specialist Lam,” a man said. The other ships were 2.2 light-minutes away, which could reduce conversation to a series of interruptions. “We’d like to see the first column again. Stand by for auto control.”

“Roger that,” Lam answered, holding his hands up to Bauman in an apologetic shrug. Then he switched frequencies, preparing for new signals from the PSSC ship.

His suit adjusted his upper body, aiming the gear block on the side of his helmet with machine precision. His movements were a little spooky. Their suits weren’t supposed to accept remote programs without an okay from whoever was inside, but Vonnie anticipated trouble.

When they left the trench for the tunnel, would their suits lock up? If they tried to send their data on public channels, would the broadcast come out clean or garbled?

Lam switched back to suit radio. “There’s something embedded in the ice!” he said.

“What?”

“The AI must have seen it in our telemetry. I have a new grid showing pellets inside the carvings, one at the tip of every arm. Look. They’re some kind of organic material.”

The miniscule spheres were as translucent as the ice itself.

“Are those eggs? Food?” Bauman said.

“What if—” Vonnie said, trying to get a word in edgewise.

“We can’t pull them, not yet,” Bauman said. “We’ll have to record and map it first. I guess your full spectrum burst is the best way to go, Lam. What do you think?”

“I think you’re right,” he said generously.

“Can we push a wire in? Get a sample?”

Vonnie gestured. “What if we pick through the debris against that wall?” The fourth column was the most deteriorated. Among the cluttered arms were thirteen that had crumbled, leaving piles of ice on the floor.

“You’re a genius,” Bauman said as she clapped Vonnie on the back, a dull clank.

Moments later, they had their sample. Lam and Bauman crouched over it together like cavemen protecting an ember, bumping their shoulders, both of them chattering on the radio.

“The pellet weighs six point two grams,” Lam said, balancing it in his glove.

“It isn’t an egg, and I don’t think it’s a food substance, either,” Bauman said. “From the consistency and methane traces, it looks like digested waste.”

“You mean it’s feces,” Vonnie said.

“More than that,” Bauman said. “The pellet was molded with other biologics like saliva or blood. It’s swamped in hormones. It’s a message.”

“What does it say?”

“It could be a marker or a name. Everyone’s smell is unique.”

Vonnie wrinkled her nose. “You mean they sniffed it?”

“Or tasted it.”

Vonnie thought that was pretty gross, but she understood why Bauman admired the elegance of the medium. In this resource-limited environment, the carvers had found at least two ways to encode information, first shaping the ice, then preserving flavors or scents.

“So they were like dogs,” she said.

“Maybe. We won’t know until we get more samples under analysis. Are the pellets all the same? Are they different? This might have been a library. The hormones could trigger fertility, pubescence, molting, anything.”

“You think they were sentient,” Vonnie said, and Lam answered, “Yes.”

“We don’t know that, either,” Bauman said.

“Dogs don’t build libraries,” Lam said.

“What if this is a bathroom?” Bauman said. “We might be standing where they relieved themselves.”

“Nobody puts their latrine on top of their living quarters. If this is a bathroom, it would be further down. Right? Plus it took a lot of work to store the pellets in the wall.”

“That could be a function of avoiding predators or a way to keep from fouling their air. We don’t know.”

Vonnie’s friends might have stayed in the trench all day, absorbed in their chem tests and new theories. They might have been satisfied with this discovery and stayed until the other ships arrived.

She was the one who convinced them to move on.

“Why don’t you two quit playing with that guck and help me,” she said, laughing. “Let’s go.”

9.

When she started down the tunnel, it was with the thrill of history. Her exhilaration felt like a shout. She would always be first to walk inside Europa, and a slavecast kept a swirl of relays and burrowers around her feet, recording everything.

She wasn’t as graceful as the mecha. The passage dropped steeply. Misjudging the gravity, she tended to bash into the ceiling. Then the opening shrank until it wasn’t much bigger than her suit. Again and again, Vonnie was forced to drop to her knees or roughly shoulder through.

Her telemetry betrayed them. The men on the radio questioned her movement and ordered her back. She kept going. Sonar showed an end to the tunnel after four hundred meters, yet infrared revealed that the end was a shade warmer than its surroundings. Hot pinpricks of gas were bleeding through.

“There’s something on the other side,” Vonnie said. “My sensors are going nuts.”

“Something alive?” Lam asked.

“Stop,” the radio said. “Specialist Vonderach, acknowledge. You will comply.”

“Roger that,” she said. “But this is an air lock. Look at it. It’s too smooth. It definitely isn’t a formation caused by melt or tidal pressures.”

She cringed at the idea of giving such responsibility to anything as flimsy as ice, but there were no metals here. What else could the carvers use? It spoke again of their inventiveness and determination. She couldn’t wait to see more.

Opening the end of the tunnel was a chance to show her worth to the team. To get through without losing the air, Vonnie would need to trap herself between the lock and a new seal of her own making — and every surface in the ice showed old scars and stubs. Irregular holes marred the walls where building material had been dug out and replaced.

“I say ’go,’” Lam told the men on the radio. “We’re picking up too many readings. Noise. Heat. We could miss something significant if we sit here.”

“I can get us in,” Vonnie said.

The debate among the high-gee ships was maddening. The Brazilians wanted her to withdraw. So did Naomi Harada, the Japanese minister aboard the American craft.

“What if our guys listen to them?” Vonnie worried, but Lam said, “No, Brazil is doing our work for us. Watch. Nobody likes being told what to do.”

He predicted the chain of events flawlessly. The Brazilians were frustrated that they had none of their own people on Europa. Their demands for international unity were terse, even petty. They cited old grievances against NASA and the ESA. They called on China to support them.

Ignoring their objections, the leaders of the Chinese, American, and European space agencies reached a consensus: Vonnie should continue.

“Yes!” she said, pumping her fist in excitement.

Lam grinned at her like a kid.

They gathered near the air lock. Bauman was last in line, so Vonnie took control of Bauman’s suit, assembling frozen hunks in a stack and soldering the pile together with her laser finger on a minimum setting. “Slow work,” she apologized, not wanting to dull their energy.

Lam shrugged, running sims on his visor as he waited. “Think what the carvers used instead of a laser,” he said. “Body heat? Urine or saliva? There are organic contaminants everywhere.”

“Lots of DNA,” Bauman agreed happily.

At last they were sealed in. Vonnie eased through the original lock and saw another ice plug further on. Redundancy was good engineering, but she was disappointed to realize how many lifetimes it must have been since the carvers had visited the tunnel or even considered it important.

Long, long ago, the top of the next air lock had slumped open. Her suit analyzed the low-pressure atmosphere wafting past her as 98.9 percent nitrogen, a gas so inert that no creature could have evolved to burn it as an energy source. This seemed to be a dead area. Why bother to block it off?

“There’s nobody home,” Vonnie said.

“Knock knock.” Lam was cheerful, even buoyant, bumping her arm as he tried to look past.

“Maybe the air is bad because this tunnel is unused,” Vonnie said. “Oxygen could be their most closely guarded resource. They might control it with flood gates.”

No answer. Lam and Bauman were beyond listening to her, lost in the chatter of data. Their tiniest mecha had run ahead while others lingered to examine the ice. Lam especially was in his element, pulling files and fitting each perspective into a working whole.

Vonnie was eager, too, yet she meticulously rebuilt the locks behind them. Then she moved in front again.

After another eighty meters, the slanting tunnel dropped into a sink hole. The vent was encrusted with old melt. Across from her was a hollow of uncertain depth. Stalactites hung from the top of the shaft.

There had been a catastrophe, probably a belch of heat. If the carvers had built anything else in the area, it was gone, but Vonnie couldn’t feel sad.

She walked to the edge of the hole. Her sonar raced down the shaft like a fantastic halo, never reaching bottom. The hole appeared to drop for more than a kilometer, twisting, widening, and branching away.

Somewhere down there was the dark heart of Europa.

“Perfect,” Bauman said. “This sink hole is a natural cross-section through the ice. How far down can we take samples?”

“Give me a minute,” Vonnie said. It would be easy to secure a few bolts, play out a molecular wire, and let their mecha descend like spiders. She rifled through her tool kit.

“Huh,” Lam said, taking control of a burrower near Vonnie. The machine scooted away from her and joined him.

“What’ve you got?” she asked.

“I—”

Later, Vonnie played back their group feed. Cursing him, she understood. His radar had probed a swath of dirty ice in the tunnel wall. Most of the patches that interested him were impure. Some were stained with lava dust, others discolored like milk or glass.

He’d noticed a shell — a small, spiral shell lodged in the wall of the tunnel. It wouldn’t have looked unusual on any beach on Earth. On Europa, it was a treasure.

Lam’s suit had reported the shell’s position to their grid, but he couldn’t leave it alone. He needed to be involved. Under his guidance, marking the shell for retrieval, their burrower stabbed a radio pin into the wall.

The ice exploded with black rock.

Vonnie was standing beside the largest mass. Somehow that saved her. The burst of ice and rock knocked her upward, although she was snarled in her wire.

Bauman yelled once: “Lam, get back!”

There was probably no more than a quarter ton of debris stopped up behind the dust pack, a collection of gravel and stones that had gradually sunk into a loose, dangerous bulge. It weighed a thirteenth as much as it would have on Earth, but in this gravity, it splashed.

It tore apart the sink hole. Other veins of rock caused a vicious swell. The heap rose, spread, and settled again like a cloud.

Vonnie escaped the worst shockwave, half-conscious and confused. She was thrown to the top of the vent as her friends disappeared. Their sharecasts clamored with alarms and one massive injury report before their suits went dark. But she was tied to the wire, and it would not break. One end caught in the heaving ice.

Then the avalanche took her, too.

10.

The first pocket world in the ice would always be her favorite. It was inhabited by two peaceful species of bugs which were related to each other, yet were unlike the fat-bodied ants brought up by the ESA rover. They seemed to feed solely on the gray bacterial mats that grew alongside the wells of a hot spring, where the melt was thick and ever-changing.

Once upon a time, this chamber must have been part of more expansive catacombs. Ice-falls had long since closed it off. Vonnie had only stumbled into this dripping space when she refused to be deterred and started digging.

Her mind had felt very, very small in those hours — too small for any thought except to get away from the lethal, creaking weight of the collapsed vent above her.

Deep radar let her identify load-bearing sections in the ice. She’d climbed, cut, excavated and squirmed from one miniscule safe zone to another, using her arms like shovels, numbly reaching forward more times than she could count. Her knees and belly ached from contorting through the gaps.

She remembered listening for every groan and crack in the ice. She remembered the red bar of an alarm on her visor warning that her air reserves were at sixty minutes.

Her endless crawl had stopped, perhaps forever, as she curled herself in a hole no larger than a coffin to rig an electrolysis unit from her tool kit. The job became her entire focus. She was in shock, and concentrating on an attainable goal was exactly what she needed.

She assembled two electrode plates, a pump, and a compressor inside a slim steel box. She mounted the unit on her shoulder, then fed ice into the hopper, separating the oxygen from the hydrogen. Her cylinders recharged. And if her new air was contaminated, if there were Europan microorganisms or toxins in the ice, what choice did she have? Cooking the ice should sterilize any pathogens. Her screens showed no detectible sulfurs or dioxides. Nor could she smell anything peculiar.

When she finally emerged into the pocket world, she was startled to realize how much time had passed. She’d been worming through the ice for the better part of an Earth day — nearly twenty hours.

She wasn’t hurt except for a sprained elbow.

She was alone.

Not one of her comm links were active. The relays she’d left above the sink hole must have been scattered and crushed when the vent collapsed. Maybe she’d fallen further than she thought.

The pocket world was safe, but she couldn’t stay. The other ships were seventy-five hours out and it would take them several more hours to gear up and scout for her, even longer to forge their way through the crumbling mass.

She had to find a way back to the surface. She could continue to replenish her oxygen and water supplies from the ice, but she’d gorged herself as soon as she’d noticed her hunger. Her suit offered top-of-the-line meat dishes, pastas, fruits, and desserts like only the wealthiest people on Earth could afford, with the caveat that her meals were pastes fed from tubes inside her helmet… Now bulk was more critical than nutrition or pleasure. She would have traded every fruit pack and candy for more carbohydrates.

Her remaining supplies might last eight or nine days, twelve at the outside. Before then, she would get weak.

Could she eat the bugs?

No, she thought. It wouldn’t come to that. It couldn’t. Besides, they might make her ill.

She regretted not having beacons to leave in the pocket world. Bauman especially would have been enthused by the bugs, but most of Vonnie’s mecha were gone. She only had one left — a burrower — plus three miniature relays attached to her chest plate. She sent them exploring. Then she sat quietly, mourning and resting, even napping for three hours.

Her camera lights were dazzling in the wet ice as she gazed through her visor, comforted by the use of normal light and vision.

Discolored rimes of minerals permeated the uneven floor and walls of the cave. That meant the hot springs routinely overflowed. The bubbling water was saturated with iron and salt. It tainted the ice and poisoned the bugs, which avoided the most concentrated salt deposits.

The atmosphere was oxygen-rich, although it was nothing that would support a human being, laced with hydrogen chloride. More interesting, the pressure was five times what she’d seen near the surface, due in part to a lower altitude but mostly because this hollow was self-contained.

Neither species of bug had eyes or even the most primitive photo receptors. They used fan antennae and scent instead. They were basically helpless. Droplets fell steadily or in periodic rains. The chamber floor was pebbled with a thousand specimens sealed beneath the ice.

Vonnie collected ten bugs from each species and put them in her chest pack, then added samples from the bacterial mats.

The mats were vital evidence to prove the foundation of Lam’s evolutionary theory. It took billions of microbes to form something large enough to be seen by human eyes. These slimes grew in blots as fine as a needle point and as imposing as a stranger’s shadow.

She thought she could identify three different strains. One reached into the air with tendril-like fuzz. Two commingled in a symbiotic relationship, possibly using iron and water for food. This pale muck had learned to expand from the hot springs onto the ice. Vonnie supposed it used layers of dead material as insulation. Maybe it fed from the melting surface.

One thing was obvious. The bugs’ mortality rate, while high, wasn’t enough to keep them from outgrowing their food source. This pocket ecology was more than incomplete; it was unworkable; it was temporary.

Vonnie was frustrated when she built Lam’s ghost to help her. Doing so was illegal, but she was beyond any concern except survival.

Her first words to him were harsh. “Hey. Can you hear me?”

—Online.

“Your name is Choh Lam. You killed yourself and my friend because you couldn’t wait five damn seconds for an engineer to tell you not to bang on the ice.”

—Consolidating files.

“Never do anything again unless I tell you. Understood?”

—Negative. What are my instructions?

“I need to know where I am. Can you piece together my coordinates in relation to the surface?”

—Negative. Further access to core systems required.

“Goddamn it!”

Throughout Europe and North America, combining human mem files with low-level AIs was forbidden. Organic minds were extensive, subtle, and predisposed to neurochemical and emotional imbalances. Failing to place the slightest piece of the puzzle could have severe consequences.

Duplicating the living or resurrecting the dead also crossed ethical lines and medical considerations. In her childhood, thousands of court cases dealing with family, property, and tax laws had led to a widespread revulsion for electronic personalities. Many of them were distorted nightmares of themselves.

Some cultures stood as exceptions. China and Korea permitted human-based AIs, keeping their ancestors with them. In the Middle East, there were immortal holy men.

Vonnie didn’t have the computing power of those governments. Most of her suit’s systems were Level VII intelligences. Each one was a task-specific processor. Those subroutines accomplished intricate feats like her visor’s retinal response program and brute work such as balancing 220 kilos of armor in motion without falling over.

If idle, each system functioned as spare memory. They were intended to draw on each other in crisis. By permanently linking a hundred subroutines, Vonnie created enough quantum memory to host a Level II intelligence with self-awareness and personality, but she was angry at Lam and afraid of dying in this impossible world.

Bauman would have been a better companion. Vonnie wouldn’t have tried so hard to control her. The disaster she made of Lam was erratic because he was missing too much. She wanted him to be cautious, even timid.

She didn’t trust the result.

When her mecha reported a mild current of atmosphere 1.9 kilometers from the bugs’ home, Vonnie shut down the ghost. She called her mecha back to her. After they rejoined her, she attached the minis to her chest in their carry sockets and made sure the burrower was slavecast to her suit.

She dug her way through old cave-ins and membranes of ice, following a conduit left by the minis. From their data, she knew there were more vents nearby.

As she clawed at the ice, she felt another aftershock. Maybe she’d set it off by undermining a weight-bearing formation. There was a ponderous groan. Then the ice heaved, slamming at her knees and chin. Her surroundings gave way and she fell tumbling into the white.

“Help me!” she screamed. “Lam!?”

—Online.

“Stabilizers! Get my suit turned around!”

Grabbing at loose hunks and powder, she couldn’t tell up from down. Huge pieces crashed against her. The rest of the avalanche felt like quicksand or a waterfall. It rushed and billowed, taking the burrower away from her. In seconds, the burrower’s signals faded.

Her suit was equipped with gyroscopes, but her gyros were one of the systems she’d hacked to make room for the ghost. That was why she’d reawakened him.

With his help, Vonnie located an enormous wedge. She clutched at it as the flowing ice pounded on her helmet and back. Radar indicated a house-sized slab. Unfortunately, it began to rotate beneath her weight. In a minute, maybe less, it would roll and dump her. She scraped at it with her fingers and boots, trying to keep her balance — trying to locate a bigger chunk — but her sensors were inundated with noise and motion.

“Analyze my datastreams!” she shouted. “Which way should I go?”

—What is your destination?

“Solid ground. Anywhere.”

—Where are we now?

Certain she was in her grave, Vonnie gave him limited access to her mem files, enough to explain that the fallen vent where he’d died must have flattened out against the surrounding area, causing other networks to collapse. Now those implosions were also pushing down or sideways.

The ghost handled this job well. Based on her data and current sonar readings, he created sims to predict the worst of the ice falls.

Vonnie labored to free herself, sinking ever deeper through the mayhem. She struggled for nine hours.

To keep up her stamina, she ate more than she wanted, barely tasting the venison-flavored protein or faux baked potato. Nonstop exertion also took its toll on her oxygen supply. Each bite, each breath, shortened the time she had left.

Losing hope, a queer thought struck her.

This was no ocean into which she was descending — it was Europa’s sky. Captured here, native species would have no concept of anything further up. They would look for the mountains or the liquid seas below, so she began to dig beneath herself instead of laterally, no longer fighting the avalanche but using it to her advantage, sifting, swimming.

Eventually she fell onto a vast, black slope of lava rock. Whether it was an island suspended in the ice or a true mountain, she couldn’t say, but she had come down out of the frozen sky.

11.

The catacombs had formed eons ago when liquid magma cooled irregularly, leaving tubes and caverns within a larger mass. Running water cut through every opening as geysers, rivers, and slow-draining seas. Quakes opened new fractures and closed others — and the ice was always there, dripping or pushing or smashing into the rock.

In solitude, in silence, Vonnie thought about her dead friends too much as she walked.

The darkness led in every direction. There were pits and outcroppings and blind corners and slides. Once she found a sheer abyss that plunged for hundreds of meters. More often, she couldn’t see more than a stone’s throw as she picked her way through the maze.

Using an inertial compass to maintain her heading east wherever possible, she tried to keep busy with her maps and data. The atmosphere in these lava tunnels was mostly water vapor, carbon dioxide, and the ever-present nitrogen along with trace poisons. It was also warm — a few degrees below freezing.

Vonnie assumed she’d entered a fin mountain. Most of the rock formations near Europa’s surface were ejecta, cast into the ice by ocean-floor eruptions or broken off from mountaintops by the pressure of the frozen sky. If she’d discovered a dead block of lava floating in the ice, it might absorb the sparse amounts of heat generated by friction, distant lava flows, and hydrothermal vents. These catacombs were too warm. Some areas were ringed with scum like filth on a bathtub. Her suit detected sulfur, salt, oxidizing rust and minerals, all evidence of past floods and smoke and ash.

She was inside a volcano.

Europa’s molten core, silicate mantle, and low gravity created towers of unimaginable heights. The great ocean cooled many fissures and vents, driving the lava upward. Because siliceous magma was cohesive — like syrup — it trapped gases within it, lifting each eruption even further.

On Earth, in full gravity, the Hawaiian volcano of Mauna Loa rose seventeen kilometers from the Pacific floor. On Mars, in 0.38 standard gravity but without an ocean to support it, Olympus Mons rose twenty-five kilometers into the Martian atmosphere. On Europa, in 0.13 standard gravity, Lam’s sims had predicted unstable piles of rock as tall as sixty kilometers. He assumed the ocean floor wasn’t uniform. There must be shallower regions were the mantle formed plateaus. The volcanoes that scraped the surface rose from these highlands.

Fire and ice.

The volcanoes eroded and reformed at speeds much faster than any Earth equivalent, so Vonnie listened for seismic activity and swept her infrared through the caverns, looking for hot spots.

She found specks of condensation, then puddled ice before she walked into a length of catacombs that had been invaded by a creeping swamp. Giant lumps of ice sat on the tunnel floor beneath pillars and stalactites. Frozen lakes flowing at less-than-glacial speeds made waves and swirls against every strewn hunk of rubble.

The landscape was stunning, but it couldn’t soothe her as she hurried into a light wind. The pressure differential indicated an even higher temperature somewhere ahead. Maybe there were gas vents or bubbling springs.

Vonnie had seen bacterial mats and a few spores of what appeared to be fungi. She took samples of these pale bulbous growths, glad to find life of any kind, but only the ice truly thrived in this environment. When her radar identified another sun-shape on the wall, she thought it was a carving.

It moved.

“Hey!” Vonnie began to jog. Just as suddenly, she stopped. The creature was 1.2 meters wide, a round body with eight arms. She didn’t want to scare the little thing. She was three hundred meters away, and there was a chance she’d gone unobserved.

It might be best if the creature hadn’t seen her. She wasn’t trained to initiate First Contact. The decision she made could affect nine billion lives across the solar system as humankind collided with another thinking race for the first time… but she didn’t have it in her to walk away, not here, not now. She needed this success to balance everything that had gone wrong.

Besides, what the hell was it breathing?

Vonnie felt a stab of pride and melancholy at the thought, a bittersweet mix. Bauman and Lam would have given anything to be with her.

Infrared made it clear that this creature was warm-blooded. Despite the tough, insulating layers of cartilage and blubber beneath its skin, its body heat radiated in this cold like a furnace.

In that way, it genuinely was a sun. Like a beacon or a lamp, it drew her closer.

The creature disappeared, edging behind a bump of rock. Vonnie paced toward it, sweeping her radar and X-ray up the cavern wall. Where had it gone? The wall was pocked with fissures and holes.

As she paused at a hundred meters, thinking again of Lam, she realized the carvings they’d found were literal portrayals of these creatures’ bodies. They’d thought each eight-armed sun was a letter or a word. Instead, the shapes were three dimensional images of the carvers themselves.

Searching the wall, she discovered a crevice teeming with warm bodies, eight of them — the number eight again — and yet she saw no exhalations in infrared.

Vonnie forgot everything else, although she made sure not to let her smile show inside her visor. Teeth might be threatening. She moved gently even as her head raced with astonishment and delight. She knelt to make herself smaller. Then she drew one finger in the dust, merely trying to communicate the idea of communicating. She must be a surprise to them.

I’m a friend, she thought.

Furless, streamlined, they had almost certainly evolved in water. They had no bones, only strands of cartilage through their bodies and arms. They also had no front or back that she could see, no eyes, no nose, nothing to differentiate one side from another.

On top, their albino skin was peppered with spines. Some of those defensive needles were colored with a tinge of yellow or red, likely from sulfur or mineral absorption. They had no need for pigmentation in this lightless world.

Underneath, their arms were lined with gripping nubs and richly laid bands of tube feet and pedicellaria — fine, clasping tendrils in the thousands. Some were as delicate as her hair. Others were short cords like wire.

Their squirming whiskers gave them personality. Hanging on the rock, clinging in a group, most of the creatures held up one or two arms to show their undersides, and Vonnie’s sensors let her see through their bodies in any case. They wriggled and flexed.

Are they communicating with each other? she thought. How? By touch?

They danced with their arms, brushing against each other. Vonnie imagined they used physical contact like a combination of sign language and Braille. They might read their carvings in the same way — and everything inside Europa — as they groped through the dark.

Ears were their only visible sensory organs. In the grooves between their arms, protected by knuckle-like muscles, were sphincters that opened to short auditory canals. Following their ears into their bodies, Vonnie’s X-rays lit up dense, specialized cochlear and bundles of nerves. She also saw complex fatty lobes associated with the same nerves. What were those for? The fatty structures augmented their hearing somehow.

Otherwise they had no orifices of any kind except on their bellies. Vonnie noted a few slits which she suspected were well-protected gills and genitals. Each creature also had a snub beak evidently used both as mouth and anus. Her initial scans revealed a very basic digestive system, four lungs, two hearts, two hypertrophied kidneys, a huge liver, and more brain tissue than she would have envisioned in a meter-wide creature.

You’re perfect, she thought.

They were small enough to subsist on minimal food, yet large enough to build. Lungs and gills also allowed them to travel in any medium. Did they still make their homes in water? Where were their children?

“What should we call you?” she asked, forgetting herself and speaking out loud.

She remembered her friends’ energized laughter. Bauman might have called the natives octopods or aquatic mammals. More politically minded, Lam would have said Europans.

“Sunfish,” Vonnie said.

Naming them, she felt wistful and right. Sunfish was pretty. It was poetry. They looked like giant starfish, but starfish would have been demeaning.

These weren’t simple, mindless sea creatures. They were clever and brave. For the sunfish to cover as much distance as they had to the top of the ice was remarkable. It spoke again of strategy, organization, and engineering. That they’d mastered this environment was even more impressive because their lungs were too compact to hold air for long. They must have evolved some trick of oxygen compression… saturating their blood… breathing water or good air before leaving one safe zone for another…

The air locks implied they weren’t nomads. Instead, they constructed strongholds.

Am I near their home? she thought.

Then she was out of time. The sunfish leapt at her and Vonnie stepped back, stunned, as they burst off the cavern wall like shrapnel.

The sunfish were spectacular in flight. Four of them ricocheted through the crags overhead, banging into spaces she hadn’t noticed until they darted in and out. The others kicked off the tunnel floor. As soon as they were airborne, they somersaulted, leading now with their undersides and their beaks. They came in a swarm with all arms outstretched.

In that split second, Vonnie realized their carvings were a lie. The shapes etched into the trench had been smooth, stylized, and immaculate. Those carvings showed the top portions of sunfish without age or injuries, when in reality their undersides were rough with scar tissue and missing hunks of pedicellaria.

Their true selves were as grotesque as those wounds.

The first sunfish struck her helmet off-center, attacking her gear block. Others collided with her arms and chest, trying to bring her down. Vonnie staggered, but her suit kept her upright.

Her retreat was confused. She tripped over a boulder and fell as three bodies clawed at her.

She stood like a drunk, flailing with adrenaline. Many of them seemed to have disappeared. She struck wildly at the sunfish hooked around her face.

They dropped the ceiling on her. A hundred flecks of rock clattered against her suit, and she looked up as a ragged hunk as big as a car slammed down. When most of the sunfish had bounced away from her, they’d leapt up and scrabbled at the rock, digging and prying, using themselves as pistons to accelerate their weapon.

They were ruthless. Impact killed one of their own and hurt three more. It also destroyed her.

Inside her helmet, her skull whacked against the buckling armor, where torn circuitry scraped open one of her corneas. Then she hit the ground. Systems failure was total for 3.1 seconds and Vonnie sprawled in the dark, bleeding and twitching.

12.

“Are you there?” she gasped, blinded by a wet mask of gore.

—Online.

“Run! Get me up!”

She felt the sunfish against her suit, snaking through the rubble to reach her foot, her arm, her shoulder. Their arms beat at her like clubs.

Pain speared through her elbow as the suit twisted free. She rose. Inside her helmet, she shook her head, squeezing her left eye shut, but her vision wouldn’t focus and she couldn’t get her other eyelid to close at all. That eye was a numb, oozing bag mashed in a crater of flesh.

I can’t see, she realized.

Her fear became a firebrand, scalding her brain. She couldn’t think. “Run,” she said, but the ghost needed more information.

—Destination?

Something hit the back of her head. More impacts dropped her to her knees, and she screamed, “Run! Run!”

—Destination?

Vonnie summoned the words she needed. “Retrace my path for two kilometers! Retrace my path exactly! Run into the lava tunnel!”

A faint blue glow reached her good eye as the suit staggered up and turned. Probably it was displaying her maps.

My visor is intact or I’d be dead, she thought.

She leaned toward the light, peering through her bloody eye. The ruined circuitry slid into her cheek like a dozen pins. She jerked back, but she couldn’t escape. Her face was hemmed in by the sharp mesh.

Sobbing, she felt herself carried by the suit. It dashed forward, jarring her head wounds.

Then it tripped or it was knocked down. Vonnie moaned, expecting another assault. “What do you see!?” she gasped as the suit stood again.

—Define request.

“Where are they? Is there any way out?”

—There are four lifeforms in pursuit. The closest is ten meters behind us.

“No!”

—Radar indicates several branches from this tunnel, but your instructions were to remain on your path.

“Turn! Lose them!”

—Displaying options.

“Just turn! Run! Don’t let them catch me!”

The suit wrenched sideways, yanking Vonnie to her right, left, right, and right again. Reeling in agony and shock, she fought to hold onto a plan.

“Where are they now? What does the tunnel look like?”

—The nearest lifeform is twenty-five meters behind us. Displaying holo imagery.

“Fuck you! Fuck you! I can’t see!”

—Twenty meters.

“Keep running! Tell me what the tunnel looks like!”

—Radar indicates multiple side channels and cavities around the main tube, which is at least another kilometer in length. There is ice beyond it.

“What do I do?”

—Define request.

Vonnie screamed at him, using rage to overcome her panic. “How can they be so close!? You’re stronger than them! You should be faster!”

—The lifeforms are jumping from every available surface, gliding through trajectories as short as one meter or as long as thirty. Their grasp of spatial relations appears significantly more advanced than the same ability in human beings.

That helped. She was able to picture the chase. Her suit ran in leaping bounds as the sunfish flew after her. She was obstructed by boulders and pits. They acted more like arrows or balls, using long and short angles interchangeably.

“When all four of them are in the air, change course! Run into one of the side channels!”

—I anticipate such an instance in six seconds. Five. Four.

“Why don’t I feel my med systems? Fix my eyes!”

—One.

Vonnie winced as the suit flung itself backward. She thought she felt a tick of contact on her shoulder. Had a sunfish grabbed at her as it flew past?

“Where are they?”

—We’ve left the main tunnel for a chasm as instructed. The nearest lifeform is ten meters behind us and gliding further away. I’ve lost radar signals of the other three.

“Keep running! What about my eyes!?”

—Medical response appears to have been subverted by unknown packets and overrides.

“That’s you. Oh, shit, that’s you,” she whispered with a cold new sense of dread. At some point, the ghost had outfoxed the checks she’d established and tried to expand itself, fragmenting as it battled with her computers.

—Initiating diagnostics.

“No. Wait.”

—Corrupted files identified in life support nodes.

“I said wait! Off!”

Her suit froze. Vonnie toppled forward until her arm struck something. She spun around and hit twice more, bruising her leg and her back. Her face throbbed.

The pain was nothing. It was her terror that consumed her. Like a child, she reached for something to hold onto. The suit responded to manual function, letting her clutch at the rock and churn her legs.

She went four meters before her head clanged into the wall. She moved to her right, then struck something else.

What could she do?

Vonnie didn’t want the ghost to reabsorb whatever packets it had lost in its fight to control her suit. Some of those packets would be junk code. Others would be sleeper cells. If the ghost reconnected with enough of those cells, her suit’s firewalls might not win the next battle for control. But she couldn’t crawl alone through the blackness.

“Are you there!?” she shouted.

—Online.

“Where are the sunfish?”

—Radar shows no indication of pursuit.

Vonnie exhaled in a trembling gust. Were they lurking outside the chasm? Was it a dead end? The next question was the most urgent, and she fixated on it with that child-like desperation. Why? Why? Why are they trying to kill me?

If they were intelligent, they should have felt the same magic she’d experienced when she stood in front of them. They couldn’t have met anything like her before — a tall, bipedal creature in plastisteel — and she hadn’t done anything wrong. Had she?

Vonnie patted at her armor, bewildered by the mangled shapes of her torso and abdomen. Suddenly she reached for her shoulder mount. “Is my electrolysis unit intact?”

—Affirmative.

For an instant, she’d been afraid she couldn’t recharge her air cylinders. She didn’t know if she had enough gear to build a replacement.

“I should have three mecha on my chest plate.”

—Negative.

“What happened to them?”

—One was lost in the attack. Most of your tool kits and sample cases are also damaged.

“But I have two mecha left.”

—Affirmative. 1084 is missing its infrared camera and laser. 1085 registers intact.

“Detach and activate. Slavecast this suit to 85. Your function will be to translate its signals into voice mode and relay my commands.”

—Von, listen, I am more efficient than the mecha.

“What did you just say?”

—I am more efficient.

The ghost had used her name and sidestepped a direct order. How long did she have before he interrupted her suit’s systems again?

“Detach and activate 85,” she said. “Wipe all other initiatives and confirm.”

—85 activated.

The tiny mecha separated from her chest plate with a pop.

Vonnie turned her head, trying to situate herself, yearning to see. “Send 85 ahead of me into the chasm, then follow it,” she said. “Move as fast as it’s safe. Our first priority is to get away from the sunfish. Confirm.”

—Confirmed, Von.

Using her name was a simple development, and yet it was also sinister and wrong. Did he think he was her equal?

13.

Following 85, her suit ducked and bent and hopped. At the same time, the ghost narrated 85’s advisories, describing a gully, a slide, a crevice, a hill.

“I need medical attention,” she said.

—Von, I can fix the corrupted nodes.

“I want you to withdraw from life support. That’s the problem. You’re interfering.”

—Incorrect. This suit’s basic functions are compromised by external and internal damage. If I withdraw, you will lose all AI-directed systems.

So she continued to bleed. She couldn’t let the ghost work on her face. If something like her little finger had needed attention, she might have granted him access as a way to evaluate him, but she couldn’t let him repair her skull. If the procedure failed, if the ghost intentionally damaged her or shut down in the middle of surgery, it could leave her mentally stunted as well as blind. Then she might be lost down here until she starved, an idiot and a cripple, barely able to comprehend her own suffering.

Could she use 85 to reverse hack her suit? She had virtual keyboards in her gloves. She knew she could tap into 85, but she would have to do so by touch alone, without watching her key strokes on her heads-up display. She also hadn’t figured out how to keep the ghost from noticing her signals.

She needed to divert him. “How did the sunfish chase me?” she asked. “Were they talking to each other? I didn’t hear anything, and they don’t have eyes.”

—The lifeforms were emitting ultrasound.

“Sonar. Do you have recordings of it?”

—Affirmative.

“Analyze those recordings for meaning and context. Is it language?”

—Unknown.

“I want an alert as soon as you hear them again. Scan for more carvings. Anything. What else can you tell me about them?”

Vonnie snapped her hands inside her gloves as the ghost recited data; the wavelengths and compositions of the sunfishes’ sonar calls; modulation; duration; intervals. By the soft resistance that appeared against her fingertips, she knew her virtual keyboards were up.

She began to type as the ghost continued its report.

Her suit had recorded signals as low as 17,000 Hertz, within range of human hearing, all the way to 130,000, which was well above the high-pitched frequencies used by bats on Earth.

“Keep talking,” she said.

—In sunfish, the larynx is a corded muscle. Air sacs allow them to push the same air back and forth through their larynx instead of exhaling where the atmosphere is minimal or toxic. They reflect those vibrations from the horn-like material of their beaks. They…

“Why did you stop?”

—The chasm we’re following has opened into a cavern approximately seventy-five meters by thirty by forty-five. The floor drops away in a series of ravines. The far end is walled off by ice. Radar indicates fractures and melts in the ice, possibly an extensive network leading up from the rock. We may be at the edge of this mountain.

“Thank God. Go. Let’s get into the ice and try to seal it behind us. We can wall them off.”

—There is also a construct in the largest ravine.

“What are you talking about?”

—There is a rock wall sixteen meters across, two thick, and four high. It holds a reservoir of approximately twelve thousand gallons of water and slush.

“Bring me to it.”

For the first time since the assault, Vonnie felt relief. She remembered the carvings and the air locks. If the sunfish also built reservoirs, she and Lam — the real Lam — were correct in believing this was a sentient race. There were too many clues to think otherwise.

The guilt she felt was buried in fear, but it was the more honest emotion. It mingled with her shame.

How would human beings react if an alien walked into their city? Compared to the sunfish, Vonnie was a giant, and there might be schools or nurseries in the area. Maybe the attack had been her fault. Maybe she’d provoked it with her size or her smell or her heat. She should have known better. Approaching them had been selfish.

What if the sunfish were everything Lam had dreamed?

As her suit rambled down across the cavern floor, she said, “Do you see tool marks in the rock? Make sure you’re recording to mem file.”

—Cameras inoperative.

“Use radar and infrared. What’s the temperature?”

—The air is minus seventeen, but the rock shows hot spots as warm as three degrees due to thermal activity. The water varies between six degrees at its deepest parts and minus two in the shallows.

“Is it salt water or fresh?”

—Atmospheric testing suggests low levels of salinity. Should I send a mecha to acquire samples?

“Yes.”

She was curious. The majority of aquatic creatures on Earth had adapted to particular grades of water; fresh, brackish, or salt; warm, cool, or cold; sunlit, dim, or dark; but there were stand-outs like whales which could survive at least temporarily in any combination.

On Europa, there was also the matter of scalding heat. Most of the hot springs would be piped up from the great salt ocean. Obviously there were fresh water pockets such as this reservoir, melted by distant magma or by rising gases — but like the ice itself, fresh water lakes would be temporary, forever subject to cracking and contamination.

If the sunfish strived to retain fresh water, were they limited to saltless environments?

Could the reservoir have another purpose?

“Look for other ways out of the cavern,” she said. “If this is where they drink or bathe, why haven’t you seen any signs of steady traffic?”

—There are signs of steady traffic.

“Where? I told you I wanted an alert!”

—Your instructions were to alert you to sonar calls or carvings. There are four holes in the ceiling and a fifth alongside the chasm from which we emerged. Three show indications of regular movement. The rock is abnormally smooth in places or cut in bands like ladder rungs.

Mentally, Vonnie paused. The suit kept her body moving forward, but in her mind, she took a step back. She also released her virtual keyboards, cancelling her efforts to subvert the ghost. Taking him apart would have to wait.

“Get me out of here,” she said.

—Von, my scans of the reservoir are incomplete.

“Get out. Detach and activate 84. Leave it here with 85. Command both of them to generate as much noise and heat as possible.”

—84 detached.

The sunfish hadn’t let her escape. They’d watched her run straight into a population center.

Vonnie ached with horror as her suit jogged from the ravine. With luck, her mecha would cover her. Was this cavern the sunfishes’ home? The air was poison, but maybe they were inside the reservoir, breathing through their gills… waiting to snatch her leg and drag her in…

“Tell what you see!”

—We’ve cleared the largest ravine.

“Bring 85 after us. Keep 84 near the water.”

—There are disturbances in the reservoir. I estimate six lifeforms beneath the surface. Eight. Twelve. Fourteen.

His voice counting smoothly in her ear was a stark contrast to her pounding heart. “What about the ladders up the cavern wall!?” she said. “Are there sunfish above me?”

—Negative.

“Leave 85 between me and 84. Tell it to pick up some gravel and throw it, not at the sunfish and not at me. I want to distract them.”

—The lifeforms have emerged from the water. They are emitting ultrasound.

“Hide.”

Her suit shoved her down onto her knees. The most frightened part of her wanted to keep running, but the sunfish who’d let her go were probably waiting in the chasm. Vonnie didn’t want to run into an ambush. More than anything, she needed to apologize for invading their home.

“Play eight of their sonar calls for my ears only,” she said. “Were there any that sounded non-aggressive before the attack? Simulate those calls for me and prepare to broadcast on my command.”

—Commencing simulation.

Her head rang with shrill chirps and screeches. Ultrasound was imperceptible to human ears, but the ghost translated the sunfishes’ cries into a piercing equivalent.

Were there words or was it only noise? Vonnie didn’t know what she’d heard, but she wouldn’t get another chance to speak before the sunfish were on top of her. “Broadcast those same calls through 85,” she said. “If the sunfish respond, adapt your calls to match. Make sure you keep using both mecha as decoys away from me.”

—Broadcasting now.

“Where are they?”

—The lifeforms have jumped past the mecha straight at you. Contact in five seconds.

“No!”

Her mind split. As a teacher, she wanted to communicate, but the ape in her would do anything to live.

Vonnie yanked an excavation charge from her forearm and slammed it onto the ground on her left, orienting herself solely from memory. She’d worked in scout suits for years. From the earliest days of her career, she’d also learned to map busy construction sites in her head.

Her hand went to the charge unerringly. Her thumb double-flicked the safety locks. Then she aimed the shaped charge at the sunfish and flipped herself in the opposite direction.

If she had had a conscious thought, it might have been that she’d forgotten her despair. But she’d stopped thinking. She acted.

The detonation struck her suit like thunder. Vonnie cradled her helmet in her arms. A small, hard object whacked into her thigh — a rock — as something else hit her shoulder wetly — a sunfish.

It wasn’t dead. It thrashed and snapped at her gear block, ripping into her helmet.

Vonnie saw a blurry flare of holo imagery in one eye as her visor flashed orange, then red. The sunfish was about to breach her armor. Berserk with fear, she caught the sunfish’s body and squeezed her fingers into it like blunt knives, overtaxing her suit’s amplified strength. She punctured its skin. The sunfish shuddered. It went limp.

She threw away the bloody mess and hopped to her feet, falling, scrambling, falling again.

She put her life in the ghost’s hands, letting it replace her blind, pell-mell sprint with its controlled stride. “Take over! Run for the ice! Can you keep the blast zone between me and them?”

—Affirmative. Most of the lifeforms are disabled. Nine dead, three wounded.

“Where are my mecha?”

—84 is under duress. 85 is unresponsive. The surviving lifeforms are battering them with rock clubs.

And yet the sunfish had bypassed her mecha at first, even ignoring the gravel that 84 had thrown. How had they known to target her instead? Because she was larger? Why hadn’t they listened to her sonar calls?

Carried by her suit, Vonnie’s emotions swung back to self-doubt. The savage clarity she’d felt faded as guilt returned. There was a lesson there, but she was too overwhelmed to recognize it.

14.

She hoped she’d lose the sunfish in the ice. Didn’t they live mostly in water and rock? Maybe the ice was too cold or too precarious for them.

She knew she was grasping at straws. The carvings were proof that they inhabited the ice or had at one time, but grasping at straws was all she had left. She couldn’t even hack the ghost from outside her suit’s systems now that her mecha were gone, and she was dizzy and weak. The blood from her face had leaked down her chest like a growing stain.

—Four lifeforms are close behind us.

“Where am I?”

—We’re inside a seam in the ice. Radar indicates more chasms and holes above us.

“Tear down as much ice as you can! Block them off!”

The suit jostled her, hammering at the ice. Fresh pain coursed through her head. Her shredded face felt like a drum skin, sensitive and taut.

If she couldn’t reprogram the ghost, she might be forced to let him operate before she lost consciousness. What would happen then? If she slept, the ghost would keep running and climbing with her body inside it like a corpse. That could be a mercy unless she never woke up.

The suit lurched forward, left, forward again, and then backward and to the right.

Vonnie gasped, “Talk to me!”

—Two lifeforms squeezed through the avalanche I created, but I no longer have a clear radar image of their positions. There is rock mixed through the ice. Many of the openings are too narrow for us. The lifeforms may be circling around.

“Can you hear them?”

—Negative. Our sonar is inoperative.

“When did that happen?”

—During the second attack. Von, radar shows new lifeforms above and behind us.

“Pull down more ice or rock! Do anything you can!”

Her suit pummeled the walls, crabbing away from the sunfish. She felt herself wiggle and kick and dig. Once an arm tip slapped her boot. The sunfish were very near.

She quit moving abruptly.

—We’re safe. I’ve packed more ice into barriers than the lifeforms can move without laboring for hours.

Vonnie reached out with both hands and clunked her fingers against the walls. Then she pawed at the ceiling and floor. “Is there a way out?”

—Negative. I’ve sealed this pocket on all sides.

“You… Why would you…” Vonnie swallowed, tamping down her claustrophobia. She’d told him to do anything necessary to protect her, and he’d obeyed with his literal, idiot logic. “Which side has less sunfish?”

—The chimney above us held only one lifeform.

“Dig out that side before more of them come. Go. Get ready to fight.”

Her suit clawed at the ice, raining dust and heavier chunks on her helmet. Vonnie steeled herself against each blow. Pain was becoming normal.

“List all functioning sensors,” she said.

—MR-7 radar 100%. SPRD radar 100%. Bryson infrared array 100%. Mobile platform seismographs 70%. Spotlight at full power but controls intermittent.

“Wait. Is my spotlight on?”

—Affirmative.

“Turn it off!” The heat of the camera spot might explain why the sunfish had ignored her mecha at the reservoir. “Was the light on when we were in the ravine?”

—Negative.

“What about residual heat?”

—Affirmative. With intermittent function, the spotlight’s temperature has fluctuated between twenty-two and eighty degrees Celsius since damage sustained in the first attack.

“Turn it off.”

—The controls have short-circuited.

“Cut power.”

—The spotlight is slaved to the same energy grid as the radar and infrared arrays.

Should she break it with her fist? She would need the light when she regained her eyes. Even if there were spare bulbs left in her kit, she might not have the tools to extract a shattered bulb before installing a new one.

—Seismographs indicate scratching on the other side of the ice. I estimate two lifeforms are excavating this hole.

“Stop digging when you get within sixty centimeters. Let them do the work. They might get tired. Grab them as soon they come through. Throw them behind us. Jump out of the hole and knock down as much ice as you can. Confirm.”

—Confirmed.

“Can you fix my gear block? I need sonar.”

—Those transmitters are missing. There is nothing to fix.

What did that leave? Could she translate radar or infrared signals into something she could hear? Like their mecha, her suit was over-engineered, over-equipped, and highly adaptable. But there was a better solution. Her helmet contained a voice box for communicating with people who weren’t in suits. She also had hardware designed to assess injuries with ’sound bullets’ from a nonlinear acoustic lens in her chest plate.

“Run a patch from my voice box to the medical imaging systems,” she said. “I want to control the MIS by voice command. Don’t let the box make any external sound. Its function is to control the MIS. Understood? When I shout like this — yah! — make the MIS generate a terahertz pulse, then translate those signals back to me as normal sound.”

—It’s improbable the lifeforms will be able to hear frequencies in the terahertz range if you intend to broadcast their sonar calls.

“Just do it.”

Using Vonnie’s hands, the ghost began to rearrange the panel circuitry on her ravaged, filthy armor, creating a patch from her med pack to her helmet. That the sunfish wouldn’t be drawn to a terahertz pulse was good. She didn’t want to talk to them. She wanted a sensor independent of the ghost, because if she lived, her fight with him would be next.

—Here they come.

Her arms stabbed up. Her gloves clenched on squirming muscles. The sunfish squeezed their arms around her wrists as an eerie vibration passed through her chest. It was their sonar, an intimate, unpleasant buzz.

Her suit tossed them down and sprang out of the hole, chopping at the ice to seal them in.

The sunfish were too fast. One snarled itself around her boot. It hauled itself up her shins to her groin. Vonnie tried to run. She punched it loose, but the other sunfish roped four arms around her ankle, screeching.

Was it bringing more of them?

Vonnie wept as she stomped on them. They felt like rubber bumps until their bodies ruptured, spraying juice and guts up her legs. “I’m sorry! Sorry! Oh God, I’m sorry!”

At first she didn’t realize she’d escaped. In this gravity, spidering through the ice felt too much like combat — grab, kick, grab again — swimming off the walls and ceiling. She gritted her teeth and endured.

“Where are they?”

—No lifeforms in range.

“Scan again! Where are they?”

—No lifeforms in range.

Tidal pressures, heat, and gas had riddled the ice with fractures and melts. A few gaps lifted up like crazy subway tunnels. More often, there were honeycombs.

The openings teased Vonnie with dead-ends and obstacles. Sometimes her suit was able to bash through stalactites or veils of ice. More often the ghost backtracked or gave up a hundred meters of hard-fought progress even when Vonnie was desperate to hide and rest.

After 1.7 kilometers, the ghost reported more rock ahead. The ice she’d crossed appeared to fill a valley between two mountain peaks, which explained why the ice was cracked and soft. The rock formed a bowl. It radiated heat upward. It also supported this part of the frozen sky, because the mountains meant the sky could only drop so far.

Her suit leapt an abyss onto solid ground. They charged up an uneven slope, weaving among the hollows and dripping ice overhead.

—There are open lava tubes on our right.

“Pick one! Hurry!” Vonnie didn’t want to go into the rock. She wanted to climb it. But if she stayed outside, the sunfish were more likely to hear her. “Where are they?”

—No lifeforms in range.

Her suit clambered sideways and down. Vonnie counted every step. The noises around her deepened.

“We’re inside the mountain?” she said.

—Affirmative.

She wouldn’t get a better shot. Her hands tapped inside her gloves, opening her command codes. Then she launched a clumsy voice key assault on the ghost. “Authorization Alexis Six, all systems respond. Bajonett. Bajonett.”

The emergency order was meant to compartmentalize and suspend all AI activity within a suit, ship, or station. At school, they’d called it the Knife. Basic processors were supposed to take over. Instead, the ghost caused another interrupt. Feedback squealed in Vonnie’s ears. Worse, her voice box transmitted the same roar as if calling for the sunfish.

“Eeeeeeeeeeeeeeee!”

The suit convulsed, slamming her face with unbearable pain — and then she had manual control.

She ran.

Her terror left no room for thought. It made her more effective. She forgot her wounds. She forgot her exhaustion. All senses tuned to the dark, Vonnie became her own momentum, reveling in every centimeter gained. She ran with her eyes shut, chasing the sound of her own boot steps. This channel in the rock was tight enough to reflect every noise back on itself, and she dodged through the space between each rattling echo.

15.

Her frenzy didn’t last. The ninth or tenth time she fell, she paused before standing up. Then she was running again, crashing through the rock less successfully than before. Self-awareness returned in fits and starts.

Fix your eyes, she thought. Test the system. If the ghost is gone, you can fix your eyes.

Climbing, slipping, staggering, crawling, finally she accepted that she had no choice except to take her chances with life support. She decided to stop and set her trap.

When the sunfish caught up, Vonnie was hidden on a rock shelf above a short cliff. She’d rebooted the ghost with some success. He was still no better than three-quarters logic, but she’d gained control of her medical systems and the nanotech was rebuilding her left eye. The ghost had fixed the sonar receptors in her helmet, so she could hear ultrasound again even if she couldn’t transmit. The two of them had also turned off her spotlight when they stripped her gear block for parts. First she’d used the light to set her trap, burning a false trail beneath the cliff.

She should have anticipated that the sunfish would ignore it. As they stole into the fissure below her, they crept up the sides of the rift and moved straight toward her hiding place, filtering through every thin cleft and pit.

Vonnie stood to meet them with her welding laser and a chunk of rock. “I need auto-targeting only,” she said. “Fire by voice command.”

—Von, that drops efficiency to thirty percent.

“Fire by voice command. Confirm.”

—Listen to me.

Her terahertz pulse detected movement sporadically, carrying new, ever-closer signals to her ears. She couldn’t tell if there were four or forty of them hidden in the rift, but their sonar calls were all around her.

She discerned another hint of arms, then heard the clack of a falling pebble. Their voices rose like a wailing song.

Her emotions were a different storm, but there was one clear idea at the center of it. She didn’t want to die badly. She didn’t want the wrong reasons to be her last.

Should she put down her weapons and let them kill her? What would that teach the sunfish about human beings?

The ghost said:

—I have six to eight targets, all well-concealed. Ten targets now. If we’re going to pick them off before they jump, I need full system access.

But they hadn’t jumped. Not yet. The sunfish seemed indecisive. Maybe their careful approach was an overture.

“They’re not attacking,” she said.

—They’re taking position.

“Last time they came straight at me. What if I’m far enough from their home? They might realize I’m not their enemy.”

Standing at the edge of the rock shelf, Vonnie made herself small. She knelt and tucked both arms against her chest, concealing her laser.

—What are you doing?

Her posture was submissive, yet she also tried to project resolve and strength, keeping her face up, turning it from side to side in an attempt to convey alertness. The sunfish understood at least some of her physiology. They knew her sensory organs were in her head.

—Von, listen. It’s the only chance.

“No,” she whispered, making her decision. “Off.”

—Wait.

“I said off.”

The sunfish sang and sang and sang, measuring her, crowding her.

A lesser woman might have wished them dead. Vonnie hoped to befriend them because ultimately the sunfish were like her. With their carvings and their architecture, they’d had exceeded all expectations — and merely by coming to Europa, so had she.

Thousands of candidates had sneered when her file was announced as the third member of the science team. They’d swamped the boards with insults. Nice tits. Picked for the cameras. I guess she’s sleeping with the right people. Her abilities had been questioned by every jealous shithead on Earth. That they would’ve complained about anyone was no consolation. The disrespect was hard to shrug off, but how many of them would have survived the ice?

How many men would have lowered their weapons?

Vonnie was ruled by her desire to make things work. If that made her gullible or too patient or too curious, so be it. She didn’t want to fight.

16.

The first sunfish hit Vonnie from behind like a silent missile. It struck the side of her head. Then the rift exploded with bodies.

She screamed uselessly. Whipping her fist into the monster on her head accomplished nothing, either. The sunfish had landed its body against the rough mark where her gear block had been, cinching its arms around her helmet, chewing with its beak. The sound was a rubbing squeal.

Somehow she managed another sweep of the rift. The echoes from her terahertz pulse were close and frantic, overlapping. There were more than twenty sunfish in the tightly choreographed launch. Most of them had gotten past her explosives.

“Are you still there!?” she shouted.

—Von, listen. Don’t close me down again, please.

She was already yelling over the ghost. “Auto assault, max force!” she shouted. “Lam! Lam! Combat menu AP, auto assault! Confirm!”

The delay felt like another kind of blindness and separation. Vonnie screamed again, beating at the arms covering her face. The sunfish’s cartilage skin was like pounding on leather. Her cutting tool would pierce that hide, but she was afraid to use the laser.

Something yanked her sideways, hurting her spine. At first she thought she’d been hit by a mass of sunfish.

—Auto assault.

The suit threw her in a cartwheel. As it rolled, it put her fist to her temple and drew the laser across the sunfish’s arms, a precise stutter of four burns. It tossed her onto her hip and met the incoming wave with a kick.

Impacts shook Vonnie’s boot and shin. Then she was up again. Three arms clunked against her back. Some of the sunfish must have gone overhead when she dropped — they must have surrounded her — and the suit spun and rammed into the rock, scraping itself clean.

Whatever triumph she’d felt gave way to claustrophobic terror. The suit did not use its shape like a human would. It pinned one monster with its chin, then used its hip like a club against another. Again and again it hurled itself against the rock. It wasn’t squeamish. It did not flinch at the wretched shrilling of a sunfish caught between its hands or even turn from the burst of entrails. In normal gravity, against larger enemies, Vonnie would have been seriously injured. Even here she was so shaken, she didn’t immediately realize the fight was over.

Nor did she remember when she’d regained her left eye. She felt elation, then shock.

“I can see,” she said. “Lam?”

Her visor was peppered with chip marks and abrasions. It was opaque in the middle. A gouge the length of her finger ran across her nose. The sunfish had almost bashed through.

Given another chance, they might succeed.

Vonnie glanced through two unmarked portions in the synthetic diamond, bending her head to improve her vision.

She stood at the top of the landslide beneath the cliff near her explosive charges. The rock was streaked with rimes of salt. Crusty white patches had seeped from the ceiling, but she was unable to peer into all of the holes overhead. Were there more sunfish above her?

Half of her display was inoperative. The rest of her visor glowed with heat signatures, although the only living shapes were fading as the sunfish retreated. Eleven bodies lay impaled against the black lava. In the minimal gravity, the air was fogged with blood.

Mute, she tried to turn away. Crying out, she knew she was paralyzed. The suit didn’t respond to her arms or leg or head.

“Lam?” she said. “Lam, it’s over. Off-line. Lam, off-line.”

If the sunfish attacked again— If the ghost controlled all suit functions— Her body choked with that heavy new fear, and she fought without thinking inside her shell. She screamed when she was unable to move even slightly.

He spoke in a hush:

—I have an additional threat.

“Let me go!”

—Von, quiet. Something’s coming.

“What?”

—There were new sonar calls right before the sunfish withdrew. Something scared them off.

“Is it one of our probes?”

—No, these are new lifeforms.

Vonnie nodded bitterly. Food here was scarce. Any commotion would draw every predator within hearing.

If there was good news, it was that the ghost’s voice had changed. He seemed cooler and more confident. This was the first time he’d called them sunfish. That he’d said no instead of negative was another indicator of health. Had he actually written out his glitches? With access to more systems, he could have duped himself and then cut away his flaws in a microsecond. She was overdue for a little luck.

He said:

—Do you want to stay and fight? I estimate they’re four hundred meters away.

“How fast are they moving? Are they big?”

—Judging from their sonar calls, they’re at least as fast as the sunfish. They’re also louder. They may be larger. They’re within two hundred meters now.

Each breath came in a short, tight rhythm. Vonnie tried to calm her lungs and failed, hating her own seesaw of emotions, hating the darkness and her pain. She felt like apologizing even though he was a goddamned program. She felt grateful.

Would he pass a diagnostic? If he’d attained full logic, the two of them would be a force to reckon with now that she could see again, but she was reluctant to put him to the test, not in combat, not even for the chance to take recordings of another major lifeform.

“Run,” she said. “All these bodies, that should be a fat meal for whatever’s coming. They’ll stay to eat. Let’s get out of here.”

17.

Her suit leapt down from the cliff and hurried away, putting distance between them and the new predators. Unfortunately, Lam changed course seven times in five minutes through the spongy, jagged rock.

Vonnie tracked their progress with a heads-up display as they scrambled through gaps and pockets, jumping a crack and two loose hills of debris.

The ghost sought every possible way up, but they kept losing as much elevation as they’d gained, ducking and weaving for open space. They were forced left, then down, then down again through a pit laced with dry crunchy webs of mineral deposits. It felt like they were running in circles.

“Go back! Lam, go back to that last branch.”

—Radar suggests another upward trend ahead of us.

“Aren’t you headed where we came from?”

—We’ve paralleled several caverns, yes.

“Christ.”

She’d taken the explosive charges with her, so it would be easy to blow the channel behind her and shut off any pursuit, but what if she encountered another foe? What if this tunnel was another dead-end?

Between radar sims and actual footsteps covered, Vonnie’s maps went twenty-two kilometers, although most of that was tangled into a pyramid just eight klicks on a side. Some sections of her trail had also gone unrecorded or were literally nonexistent now. Colossal shafts of ice had been pulverized when the sink hole collapsed. It was unlikely she could retrace her steps even if she wanted to.

“What can you tell me about the new lifeforms?”

—They used many of the same frequencies as the sunfish. I estimate there were only six of them, but the sunfish retreated within seconds of hearing the other sonar.

Vonnie examined a wide vein of rock as they approached. It looked like an excellent place to drop the roof. All she wanted was out. No more data, no more diplomacy, no more trying to vindicate her friends’ deaths. No more guilt.

“If they’re ahead of us, we need to be prepared.”

—I’ve continued to see traces of prints and spoor. Look there. And there.

Across her display, the ghost highlighted four smears of feces on a level spot on the tunnel floor. None was more than a few frozen blotches. In the frozen sky, nothing went to waste or was left behind.

That made her feel awful again. Compared to Europa, her planet was unspeakably rich. She wasn’t sure if it was even possible for her to comprehend how their poverty affected them.

Did the sunfish routinely scout the impermanent, snarled labyrinths in the ice? That could account for why they appeared to know these dead zones so well even when there was no food, no breathable air, and only a few drips of liquid water for them to use for oxygen. She’d seen no food sources other than the bugs, bacterial mats, and a few blots of fungi.

Was that why they were chasing her? To eat her?

She recalled the admiration she’d felt when she first connected the sunfish with the carvings at the top of the frozen sky. She’d supposed they explored the highest reaches of their world in the spirit of adventure, like people climbed Mt. Everest… like she’d volunteered for this mission… but she’d ignored the reality of Lam’s models.

On Earth, a balanced ecology had reestablished itself after extinction events like the eruption of the Toba supervolcano or the Chicxulub meteor strike. On Europa, vast swaths of the biosphere had vanished completely, either burned to nothing or devoured by the ice.

Their environment was a patchwork mess of isolated survivors. What if the sunfish were so desperate for calories, they had no choice except to sweep through the ice looking for anything to sustain them?

Pity. Empathy. Vonnie was glad to feel emotions other than revulsion. It kindled something new in her.

For an instant, she was optimistic.

“Why would they gather their feces instead of leaving it as markers?” she asked. “To hide themselves from predators? For fertilizer?”

—That implies they’ve developed agriculture.

“Farms, yes. Why not?” She practically smiled. Haggling with the ghost reminded her of talking to the real Lam. “They could grow fungus for food.”

—It may be more likely that they use dung for insulation or cement. It would be difficult to seal rock structures with ice.

“Cement,” she said, brooding out loud.

The sunfish might have camouflaged a hundred passageways around her, covering traps and doorways with matching rock. The ghost would sense any that weren’t airtight, but how many clues had she missed?

“Tell me what you can about the dung and give me a detailed read if we find any more.”

—I believe the feces belonged to the new lifeforms. We’d need to stop for a thorough analysis to confirm, but it contained unique, indigestible nubs of cartilage from the sunfishes’ arms. It also looked to contain high concentrations of sodium chloride.

“You mean salt.”

—Yes. The sunfish carry it in poisonous levels in their skin.

“So whatever pooped here, it eats sunfish.”

—In retrospect, there’s a high probability the sunfish pursued us beyond their territory and we’re now in the home of the new lifeforms. Alternatively, these catacombs may be no-man’s-land where both sides conduct raids on each other.

Vonnie shook her head. Even with her weapons and size, she hadn’t been able to make the sunfish run away. Whatever these other creatures were… if they scared the bloodthirsty sunfish…

Maybe she’d been luckier than she thought.

18.

Her suit scampered into a hole like a storm pipe. Then her right knee gave out. Vonnie smashed into the rock and bounced away. In the air, she tensed, fighting to keep her face from hitting next.

Her suit hurt her neck when it contorted like a cat. Lam patted her left heel and one hand against the wall, correcting her spin before he regained speed and clawed up through the maze with her bad leg trailing awkwardly, protecting it.

“Lam?” she said. “Thank you.”

—Are you injured?

“No. Uh, no. Don’t interface with the med systems. My leg’s okay. Tell me about the suit.”

—Every anterior cable in the knee snapped and one medial.

They were falling apart. Her armor had never been intended to take this kind of abuse. Vonnie wasn’t doing much better. She was punch-drunk on stress and stimulants. It had been sixty-one hours since she’d slept. She didn’t want to make the wrong decision.

“How long for repairs?”

—Without the proper tools, our best option might be to scavenge material from the ankle, weld it solid, and restore some function to the knee. I estimate that would take an hour.

“No. Keep going.”

If they stopped, she was afraid she’d close her eyes. She should rest, but closing her eyes would feel too much like being blind again.

According to his sims, they were approximately two kilometers down. Soon they needed to transition from rock to ice. This mountain rose up like a fin, always narrowing, disappearing before it neared the surface — but there would be islands suspended in the ice, free-standing hunks as large as Berlin and gravel fields like sheets and clouds. The trick was to find a gas vent that went all the way up. The trick was to ascend without touching off a rock swell.

Vonnie avoided the thought. Too much planning would overwhelm her.

They ducked a bulge in the ceiling and the gap opened into an ancient volcanic bubble. Half of it was glutted with ice, but just to look across three hundred meters of open space was disorienting. Vonnie felt the same uncertainty in Lam. The ghost scanned up and back.

“What do you think?” she said. “There’s definitely some new melt over there. If we dig, we might get into a vent. We could leave this mountain and close the hole behind us.”

He lit her visor with radar frames.

—Look.

“Oh.” Vonnie surprised herself. Even now, after everything, she felt excitement.

There were more carvings on the far side of the cavern, at least ninety columns of eight chiseled into the rock. Lam detected no organic pellets like they’d found in the trench where they’d made camp, but the information or messages contained in the symbols tantalized her.

“How fast can you record it?”

—The degradation to this site appears significant. Detailed recordings may require hours.

Vonnie limped across the cavern and pushed against a rock slab. The decayed fragments of the wall had shifted as water and ice intruded, retreated, and came again. Some wild feeling in her was able to guess which pieces were useless debris and which held carvings on one side or another.

The feeling made the hair stand up on her arms and neck. It felt exactly like… “Wait.”

—Sonar.

Somehow she’d sensed those voices before Lam, but there was no time to speculate at the weird, creeping changes in herself. “How close are they?”

—A thousand meters. What we’re hearing are echoes. They’re deep in the tunnels. They may not know we’re here.

“They know.”

—Their voices aren’t directed this way.

“They will be. Can you pull up this piece? I think it came out of that corner of the wall. If we can scan whatever’s left on it, we’ll have most of this section.”

The suit hobbled forward. How would it hold up in combat? Vonnie knew she didn’t want to fight in the open. She’d have a better chance if she found a hole and used her explosives to create a perimeter.

“It’s not sunfish, is it?”

—No. It’s the other lifeforms.

Vonnie shoved at the rock, moving feverishly now. It felt good and right to stay. She was glad to have purpose again. She would kill as many of them as she had to, but she was more than a rat in a trap, running mindlessly.

She’d worn down to the bedrock of herself and found what she needed, a last supply of courage and determination.

Seven hundred carvings would be priceless in translation efforts. This wall might be their Rosetta Stone. Vonnie couldn’t abandon it. If she ran, even if she survived, the ESA might never find their way to this cavern again. And if she died… well, if she died, some day their probes might venture close enough to communicate with her suit. It would transmit her files even if she was buried and lost.

Vonnie realized she was crying again and wasn’t angry with herself. She wasn’t ashamed. She’d done her best. Maybe that was enough.

She dropped the rock and pushed over a smaller boulder with a chipped half-sun of a carving on the underside. “Got it?” she asked, feeling close to him again, the real him and the ghost. He was a potent friend.

—They’re within six hundred meters.

“You got it?”

—Yes. There are more of them this time. Twelve. They’re moving faster.

“Help me with this big rock.”

The truth was she scarcely knew which questions to ask. She wasn’t puzzled that there were sunfish carvings in territory that was no longer theirs. These catacombs must have changed hands regularly or were deserted and reclaimed as the years passed, but she wondered why she hadn’t found more carvings, air locks, or reservoirs.

Even if the sunfish had been exiled from this area for centuries, shouldn’t she have seen other signs of activity?

Some part of the secret might be here. Vonnie was willing to defend it. In fact, she might find the answers she needed in the sunfishes’ rivals.

Was it possible that Europa had given rise to more than one intelligence species? If so, where was the evidence of a second civilization? If not, what sort of animal was strong enough to drive off a thinking race?

—I’ve finished recording this section.

“Good,” Vonnie said.

Then she swung to face the approaching voices with an excavation charge in either hand.

19.

The cavern seemed to stretch as her fear grew. She stayed near the carvings, trying to anchor herself. Deep radar let her track the new creatures while they were still out of sight. There were twelve bodies in the swarm, banging off the walls and ceiling of a gap.

—Sixty meters. Fifty.

Vonnie held her explosives. There were too many entrances, and she had only four half-sticks. She couldn’t throw one until they were almost on top of her. Otherwise they might get away, leaping back into the chasms on the far side.

—Forty.

They would catch her if she ran. She knew she had to stand her ground, but her adrenaline felt like a hundred chittering mice. She felt untamed and inhumanly quick.

—They’re in the third tunnel.

As soon as there was less rock in the way, Lam drew each body into clear resolution. They were no longer twelve overlapping blobs. They were sunfish.

“Christ, you said…”

They were different. These sunfish were larger, with longer arms and different skin, like cousins of the ones she’d fought. Cousins, yet a separate breed. To creatures who saw and spoke in sonar, the new sunfish would stand apart from the others if for no other reason than their size.

As they flitted in and out of sight, Vonnie saw they were darker, too. But they didn’t enter the cavern. Were they trying to envelop her?

Like the smaller sunfish, they must not have any idea what to make of a bipedal creature wrapped in metal and glass. That they hesitated was a positive sign.

Vonnie spoke in a whisper. “You’re recording their sonar calls, correct?”

—Yes.

“Get ready to broadcast some of those calls on my command. Can you tell me what they’re saying?”

—The pitch and intonations of their voices are different than those of the smaller sunfish, although the body shapes they use are similar.

Neither breed would be aware of their skin color. Maybe they smelled or tasted differently, but Vonnie reached one conclusion immediately because she could see. The increased mineral absorption in the skin and defensive spines of the larger sunfish suggested that they lived in the caustic waters of hot springs or the great salt ocean, unlike their smaller cousins, who might be limited to fresh water reservoirs.

Their race diverged, she thought. They grew apart, each kind finding its niche like dark-skinned human beings in Africa and pale-skinned in Europe. What if their differences are more than cosmetic? Can they crossbreed with each other?

More interesting, it wasn’t the larger sunfish who’d written on this rock wall. The size of the carvings was wrong. So was the surface texture, which matched the pebbly skin and spines of the smaller breed. The carvings belonged to the smaller sunfish. So did the nubs of cartilage Lam had identified in the feces they’d discovered.

Vonnie’s thoughts crashed together as the elusive, feinting sunfish revolved around her like a living hurricane. They dodged in and out of the gaps surrounding the cavern.

They’re eating each other! she realized. The two kinds of sunfish are at war.

Were both breeds really intelligent? Did she want them to be? If not, the situation was akin to gorillas hunting people, a larger species preying upon its weaker, smarter relatives. That by itself was horrific. But if yes — if both breeds were sentient — they were cannibals.

Yes, she thought. The word held a gruesome finality. I think the answer is yes.

The larger sunfish used group tactics like the smaller breed. These weren’t animals. Their voices rose and fell, calling to each other as individual members of the pack maneuvering for position.

They’re analyzing me. Confusing me.

Eating their cousins was disgusting, but their war with each other was the more despicable crime. It was why she’d discovered so few traces of social organization. Instead of building more safe areas, instead of farming or writing, they fought.

Their competition had been more than either side was able to withstand. In fact, she couldn’t be certain if the smaller sunfish she’d encountered were members of a single tribe or two or more. How far had their race lapsed into anarchy?

“Broadcast your sonar calls,” she said. “Let’s talk to them. You said you can…”

—Here they come.

The new sunfish sprang into the cavern, a dual wave of bodies high and low. Vonnie’s chance to kill them cleanly would be gone in seconds. She had learned not to wait, but she’d also remembered who she was and why she’d come to Europa.

“Lam, talk to them! Try to talk to them with body shapes!” she yelled.

Her suit dropped down as the sunfish flew closer. Lam greeted them by altering his stance, lowering one shoulder and waggling her hands alongside her stomach.

It was the right decision. Vonnie believed it. These sunfish were a new, separate population. She hoped they would answer her.

20.

The new breed reacted to Lam’s posture as they soared across the cavern. With a ripple of motion, their bodies shared an idea. Was it astonishment at Lam’s attempt to communicate? Vonnie realized they also used the fine pedicellaria beneath their arms to convey information. Lifting one arm or more, they showed each other dense, writhing patterns.

Many of those arms were damaged. With radar targeting, Lam identified dozens of old scars and deformities. Vonnie had seen similar gashes among the smaller sunfish. She’d thought they’d sustained those wounds on the lava rock.

The injuries were beak wounds.

When the sunfish fought, they led with their undersides, snapping and slicing at each other. In all likelihood, the smaller sunfish were better at getting inside their cousins’ reach. They would sustain more deaths, yet left more marks on their adversaries.

“Lam, hurry!” she shouted.

He was limited by her form. He was also canny enough not to try to replicate the carvings or mimic what they’d seen of the smaller sunfish. The warring breeds might have separate languages, so Lam improvised, holding Vonnie in an uncomfortable ball as he stuttered her fingers against her torso. Her visor flickered with sun-shapes as he compared these twelve individuals with sims and real data.

There was another ripple among them as Lam shifted and flexed. Did they understand?

Please, Vonnie thought. Please.

But he’d kept the half-sticks against her forearms with magnetic locks. Now he released two with a click.

—Watch out.

The dual waves of sunfish struck the ceiling and floor. They bounced toward her, intersecting with each other to create a single group.

“Please!”

They came with their beaks open, shrieking. They came with their arms thrown wide to grasp and tear.

—Auto assault.

Vonnie wept for them, monsters all of them. The intelligence she knew existed here was stunted and cold like everything inside Europa.

Lam bashed her fist up through the first sunfish, then turned to swat the next. The rest never reached her.

“Fire,” she said.

He put both charges in the wall and shattered the carvings, ducking beneath a blast of rock.

Then she turned and ran.

The four survivors kept after her, of course. She’d dreamed the show of force would be enough, but these sunfish were no different than the smaller breed. Even with two-thirds of their group dead or bleeding out, they were relentless.

Vonnie reached a tunnel and drove herself into the ceiling, crushing a sunfish on her shoulder. Lam pulled at the rock with both hands and cancelled her momentum, flinging debris back over her head. The shower hit the next three sunfish and Lam kicked downward with the suit’s arms out, clubbing them.

She left the wounded to live or die, knowing it was a mistake to let them summon more of their tribe. She knew she would always be wrong for trespassing.

For nearly an hour, Vonnie heard them behind her, crying into the mountain. The echoes faded as she climbed, except once when there were fresh voices. Had the larger breed brought reinforcements? Was there a third kind of sunfish? Their sonar calls were too diffuse to know for certain, and she was glad, dimly, muffled in exhaustion and grief.

She climbed.

She climbed without end.

Even carried by the suit, she passed her limit, her tendons straining. Something in her back gave out above her pelvic bone, grinding with each step — and in her mind it was the same, one hurt which was more exquisite than the rest.

She dug her way into a vent, leaving the monotony of the catacombs. But there was no escaping her sorrow.

The leaning shaft up through the ice looked like the sink hole where Lam and Bauman had died, although her radar showed no dust and few mineral deposits within the melt. That was a positive sign. Geysers and swells meant instability. This vent looked solid. Vonnie thought she could ascend without bolts and wire, although her hands were sore and beaten.

She climbed.

She climbed slowly, evaluating the ice, scanning ahead. Suddenly there was a new sound. Dit dit dit dit dit dit. It was the rescue beacon of a probe overhead.

Vonnie rasped out a noise like laughter as Lam returned the probe’s signals in the only manner available to him, a cacophony of terahertz and radar pulses. He repeated the chatter until the probe answered in the same way.

—We made it, Von.

“Yes.”

—Let’s wait here. Can you wait? Seven bones and tendons in your hand are damaged, and your elbow isn’t much better. I don’t want to risk a fall.

“Yes.”

—They need fifteen minutes. Can you sleep? You should eat and rest.

“No.” She couldn’t relax, hanging on the ice several hundred meters up with another quarter-kilometer to go. She kept one file open on her visor and let the data burn into her, staring through it even when she tipped her head to watch above.

Lam had put together a preliminary transcript of the carvings. With it, they had an explanation.

She was wrong.

The error made her feel not like a teacher but like a student again, because just as Scandinavian and Inuit peoples had developed multiple words for snow, the sunfish had thirty-two stances to indicate surprise and danger. Sixteen more postures spoke of moving inward to protect the pack.

Their all-or-nothing behavior wasn’t sadism or the result of animal stupidity. It was premeditated. It was a survival trait.

The sunfish possessed more imagination and mental agility than she’d believed. Like every culture on Earth, they wrote stories of other worlds and nightmares. Their carvings hinted at places and legends similar to Atlantis, vampires, and poltergeists, but their past was saturated with real-life encounters with ancient ruins and strange creatures from distant pockets in the ice and separate lines of evolution.

The sunfish had been confronted with aliens throughout their existence. That they’d never met anything like Vonnie before, that she mimicked their language and wore metal and carried tools — none of this would stop them.

To the sunfish, everything beyond the pack was a competitor for safe zones and oxygen. Everything was food. By necessity, most lifeforms in the ice had learned the same vicious reflex.

The sunfish attacked even when they were outsized or outnumbered. They’d learned to put the fight on their own terms. If they won, the pack expanded its territory. If they lost, not only did they have less mouths to feed, their dead became food for the survivors.

Until they could conceive of anything else, until they were able to conceive of anything else, their first response would always be violence.

The warring breeds she’d met seemed to be the remnants of an empire that had spread to the top of the frozen sky. Millennia ago, there had been a dormant period in Europa’s volcanic activity. Maybe someday there would be again. The carvings were short histories intended to aid the next alliance to rise from the chaos, offering commandments to share and proven methods to govern themselves in a hierarchy of scouts, warriors, workers, and breeding pairs.

Unfortunately, Vonnie had left a path of destruction through whatever civilization they’d managed to hold onto.

It wasn’t what they deserved. Worse, their kill-or-be-killed aggression would work against them now that the possibility of salvation existed at last.

What have I done? she thought.

The mecha gathering above her were American, yet relayed ESA signals. Lam pulled their search grid and told Vonnie how far she’d strayed. She was 9.1 klicks east of the trench where her team had gone in. She was also two-thirds of a kilometer beneath the surface, so the mecha rigged a molecular wire and dropped other lines around her including life support, suit support, and data/comm.

Another line lowered an emergency seal for her helmet before her visor blew out. Vonnie secured the bag around her neck, then inflated it with the attached air cylinder.

She let go of the ice. Her suit revolved dizzyingly as the machines lifted her, but the flood of voices was more intense. The men and women up top had accessed her records as soon as the data line connected. At a glance, her mem files must have looked like a running battle. She had gore and black rock mashed into every joint in her suit, her battered helmet, and her blood-stained gloves.

Someone murmured, “Vonderach, my God.”

But she was still thinking of the sunfishes’ potential and of the debts she owed, both to Bauman and Lam and to the native tribes she’d devastated. The sunfish were very human after all, with traits both good and evil. If they could be freed from starvation… If they were given a chance…

“We have to help them,” she said.