The Years Best Science Fiction, Vol. 18

Great Wall of Mars Alastair Reynolds

You realize you might die down there,” said Warren.

Nevil Clavain looked into his brother’s one good eye; the one the Conjoiners had left him with after the battle of Tharsis Bulge. “Yes, I know,” he said. “But if there’s another war, we might all die. I’d rather take that risk, if there’s a chance for peace.”

Warren shook his head, slowly and patiently. “No matter how many times we’ve been over this, you just don’t seem to get it, do you? There can’t ever be any kind of peace while they’re still down there. That’s what you don’t understand, Nevil. The only long-term solution here is…” he trailed off.

“Go on,” Clavain goaded. “Say it. Genocide.”

Warren might have been about to answer when there was a bustle of activity down the docking tube, at the far end from the waiting spacecraft. Through the door Clavain saw a throng of media people, then someone gliding through them, fielding questions with only the curtest of answers. That was Sandra Voi, the Demarchist woman who would be coming with him to Mars.

“It’s not genocide when they’re just a faction, not an ethnically distinct race,” Warren said, before Voi was within earshot.

“What is it, then?”

“I don’t know. Prudence?”

Voi approached. She bore herself stiffly, her face a mask of quiet resignation. Her ship had only just docked from Circum-Jove, after a three-week transit at maximum burn. During that time the prospects for a peaceful resolution of the current crisis had steadily deteriorated.

“Welcome to Deimos,” Warren said.

“Marshalls,” she said, addressing both of them. “I wish the circumstances were better. Let’s get straight to business. Warren; how long do you think we have to find a solution?”

“Not long. If Galiana maintains the pattern she’s been following for the last six months, we’re due another escape attempt in…” Warren glanced at a readout buried in his cuff. “About three days. If she does try and get another shuttle off Mars, we’ll really have no option but to escalate.”

They all knew what that would mean: a military strike against the Conjoiner nest.

“You’ve tolerated her attempts so far,” Voi said. “And each time you’ve successfully destroyed her ship with all the people in it. The net risk of a successful break out hasn’t increased. So why retaliate now?”

“It’s very simple. After each violation we issued Galiana with a stronger warning than the one before. Our last was absolute and final.”

“You’ll be in violation of treaty if you attack.”

Warren’s smile was one of quiet triumph. “Not quite, Sandra. You may not be completely conversant with the treaty’s fine print, but we’ve discovered that it allows us to storm Galiana’s nest without breaking any terms. The technical phrase is a police action, I believe.”

Clavain saw that Voi was momentarily lost for words. That was hardly surprising. The treaty between the Coalition and the Conjoiners-which Voi’s neutral Demarchists had helped draft-was the longest document in existence, apart from some obscure, computer-generated mathematical proofs. It was supposed to be watertight, though only machines had ever read it from beginning to end, and only machines had ever stood a chance of finding the kind of loophole which Warren was now brandishing.

“No…” she said. “There’s some mistake.”

“I’m afraid he’s right,” Clavain said. “I’ve seen the natural-language summaries, and there’s no doubt about the legality of a police action. But it needn’t come to that. I’m sure I can persuade Galiana not to make another escape attempt.”

“But if we should fail?” Voi looked at Warren now. “Nevil and myself could still be on Mars in three days.”

“Don’t be, is my advice.”

Disgusted, Voi turned and stepped into the green cool of the shuttle. Clavain was left alone with his brother for a moment. Warren fingered the leathery patch over his ruined eye with the chrome gauntlet of his prosthetic arm, as if to remind Clavain of what the war had cost him; how little love he had for the enemy, even now.

“We haven’t got a chance of succeeding, have we?” Clavain said. “We’re only going down there so you can say you explored all avenues of negotiation before sending in the troops. You actually want another damned war.”

“Don’t be so defeatist,” Warren said, shaking his head sadly, forever the older brother disappointed at his sibling’s failings. “It really doesn’t become you.”

“It’s not me who’s defeatist,” Clavain said.

“No; of course not. Just do your best, little brother.”

Warren extended his hand for his brother to shake. Hesitating, Clavain looked again into his brother’s good eye. What he saw there was an interrogator’s eye: as pale, colorless and cold as a midwinter sun.

There was hatred in it. Warren despised Clavain’s pacifism; Clavain’s belief that any kind of peace, even a peace which consisted only of stumbling episodes of mistrust between crises, was always better than war. That schism had fractured any lingering fraternal feelings they might have retained. Now, when Warren reminded Clavain that they were brothers, he never entirely concealed the disgust in his voice.

“You misjudge me,” Clavain whispered, before quietly shaking Warren’s hand.

“No; I honestly don’t think I do.”

Clavain stepped through the airlock just before it sphinctered shut. Voi had already buckled herself in; she had a glazed look now, as if staring into infinity. Clavain guessed she was uploading a copy of the treaty through her implants, scrolling it across her visual field, trying to find the loophole; probably running a global search for any references to police actions.

The ship recognized Clavain, its interior shivering to his preferences. The green was closer to turquoise now; the readouts and controls minimalist in layout, displaying only the most mission-critical systems.

Though the shuttle was the tiniest peacetime vessel Clavain had been in, it was a cathedral compared to the dropships he had flown during the war; so small that they were assembled around their occupants like Medieval armor before a joust.

“Don’t worry about the treaty,” Clavain said. “I promise you Warren won’t get his chance to apply that loophole.”

Voi snapped out of her trance irritatedly. “You’d better be right, Nevil. Is it me, or is your brother hoping we fail?” She was speaking Quebecois French now; Clavain shifting mental gears to follow her. “If my people discover that there’s a hidden agenda here, there’ll be hell to pay.”

“The Conjoiners gave Warren plenty of reasons to hate them after the battle of the Bulge,” Clavain said.

“And he’s a tactician, not a field specialist. After the cease-fire my knowledge of worms was even more valuable than before, so I had a role. But Warren’s skills were a lot less transferable.”

“So that gives him a right to edge us closer to another war?” The way Voi spoke, it was as if her own side had not been neutral in the last exchange. But Clavain knew she was right. If hostilities between the Conjoiners and the Coalition reignited, the Demarchy would not be able to stand aside as they had fifteen years ago. And it was anyone’s guess how they would align themselves.

“There won’t be war.”

“And if you can’t reason with Galiana? Or are you going to play on your personal connection?”

“I was just her prisoner, that’s all.” Clavain took the controls-Voi said piloting was a bore-and unlatched the shuttle from Deimos. They dropped away at a tangent to the rotation of the equatorial ring which girdled the moon, instantly in free-fall. Clavain sketched a porthole in the wall with his fingertip, outlining a rectangle which instantly became transparent.

For a moment he saw his reflection in the glass: older than he felt he had any right to look, the gray beard and hair making him look ancient rather than patriarchal; a man deeply wearied by recent circumstance.

With some relief he darkened the cabin so that he could see Deimos, dwindling at surprising speed. The higher of the two Martian moons was a dark, bristling lump, infested with armaments, belted by the bright, window-studded band of the moving ring. For the last nine years, Deimos was all that he had known, but now he could encompass it within the arc of his fist.

“Not just her prisoner,” Voi said. “No one else came back sane from the Conjoiners. She never even tried to infect you with her machines.”

“No, she didn’t. But only because the timing was on my side.” Clavain was reciting an old argument now; as much for his own benefit as Voi’s. “I was the only prisoner she had. She was losing the war by then; one more recruit to her side wouldn’t have made any real difference. The terms of cease-fire were being thrashed out and she knew she could buy herself favors by releasing me unharmed. There was something else, too. Conjoiners weren’t supposed to be capable of anything so primitive as mercy. They were spiders, as far as we were concerned. Galiana’s act threw a wrench into our thinking. It divided alliances within the high command. If she hadn’t released me, they might well have nuked her out of existence.”

“So there was absolutely nothing personal?”

“No,” Clavain said. “There was nothing personal about it at all.”

Voi nodded, without in any way suggesting that she actually believed him. It was a skill some women had honed to perfection, Clavain thought.

Of course, he respected Voi completely. She had been one of the first human beings to enter Europa’s ocean, decades back. Now they were planning fabulous cities under the ice; efforts which she had spearheaded. Demarchist society was supposedly flat in structure, non-hierarchical; but someone of Voi’s brilliance ascended through echelons of her own making. She had been instrumental in brokering the peace between the Conjoiners and Clavain’s own Coalition. That was why she was coming along now: Galiana had only agreed to Clavain’s mission provided he was accompanied by a neutral observer, and Voi had been the obvious choice. Respect was easy. Trust, however, was harder: it required that Clavain ignore the fact that, with her head dotted with implants, the Demarchist woman’s condition was not very far removed from that of the enemy.

The descent to Mars was hard and steep.

Once or twice they were queried by the automated tracking systems of the satellite interdiction network.

Dark weapons hovering in Mars-synchronous orbit above the nest locked onto the ship for a few instants, magnetic railguns powering up, before the shuttle’s diplomatic nature was established and it was allowed to proceed. The Interdiction was very efficient; as well it might be, given that Clavain had designed much of it himself. In fifteen years no ship had entered or left the Martian atmosphere, nor had any surface vehicle ever escaped from Galiana’s nest.

“There she is,” Clavain said, as the Great Wall rose over the horizon.

“Why do you call ‘it’ a ‘she’?” Voi asked. “I never felt the urge to personalize it, and I designed it.

Besides…even if it was alive once, it’s dead now.”

She was right, but the Wall was still awesome to behold. Seen from orbit, it was a pale, circular ring on the surface of Mars, two thousand kilometers wide. Like a coral atoll, it entrapped its own weather system; a disk of bluer air, flecked with creamy white clouds which stopped abruptly at the boundary.

Once, hundreds of communities had sheltered inside that cell of warm, thick, oxygen-rich atmosphere.

The Wall was the most audacious and visible of Voi’s projects. The logic had been inescapable: a means to avoid the millennia-long time scales needed to terra form Mars via such conventional schemes as cometary bombardment or ice-cap thawing. Instead of modifying the whole atmosphere at once, the Wall allowed the initial effort to be concentrated in a relatively small region, at first only a thousand kilometers across. There were no craters deep enough, so the Wall had been completely artificial: a vast ring-shaped atmospheric dam designed to move slowly outward, encompassing ever more surface area at a rate of a twenty kilometers per year. The Wall needed to be very tall because the low Martian gravity meant that the column of atmosphere was higher for a fixed surface pressure than on Earth. The ramparts were hundreds of meters thick, dark as glacial ice, sinking great taproots deep into the lithosphere to harvest the ores needed for the Wall’s continual growth. Yet two hundred kilometers higher the wall was a diaphanously thin membrane only microns wide; completely invisible except when rare optical effects made it hang like a frozen aurora against the stars. Eco-engineers had invaded the Wall’s live able area with terran genestocks deftly altered in orbital labs. Flora and fauna had moved out in vivacious waves, lapping eagerly against the constraints of the Wall.

But the Wall was dead.

It had stopped growing during the war, hit by some sort of viral weapon which crippled its replicating subsystems, and now even the ecosystem within it was failing; the atmosphere cooling, oxygen bleeding into space, pressure declining inevitably toward the Martian norm of one seven-thousandth of an atmosphere.

He wondered how it must look to Voi; whether in any sense she saw it as her murdered child.

“I’m sorry that we had to kill it,” Clavain said. He was about to add that it been the kind of act which war normalized, but decided that the statement would have sounded hopelessly defensive.

“You needn’t apologize,” Voi said. “It was only machinery. I’m surprised it’s lasted as long as it has, frankly. There must still be some residual damage-repair capability. We Demarchists build for posterity, you know.”

Yes, and it worried his own side. There was talk of challenging the Demarchist supremacy in the outer solar system; perhaps even an attempt to gain a Coalition foothold around Jupiter.

They skimmed the top of the Wall and punched through the thickening layers of atmosphere within it, the shuttle’s hull morphing to an arrowhead shape. The ground had an arid, bleached look to it, dotted here and there by ruined shacks, broken domes, gutted vehicles or shot-down shuttles. There were patches of shallow-rooted, mainly dark-red tundra vegetation; cotton grass, saxifrage, arctic poppies and lichen.

Clavain knew each species by its distinct infrared signature, but many of the plants were in recession now that the imported bird species had died. Ice lay in great silver swathes, and what few expanses of open water remained were warmed by buried thermopiles. Elsewhere there were whole zones which had reverted to almost sterile permafrost. It could have been a kind of paradise, Clavain thought, if the war had not ruined everything. Yet what had happened here could only be a foretaste of the devastation that would follow across the system, on Earth as well as Mars, if another war was allowed to happen.

“Do you see the nest yet?” Voi asked.

“Wait a second,” Clavain said, requesting a head-up display which boxed the nest. “That’s it. A nice fat thermal signature too. Nothing else for miles around-nothing inhabited, anyway.”

“Yes. I see it now.”

The Conjoiner nest lay a third of the way from the Wall’s edge, not far from the footslopes of Arsia Mons. The entire encampment was only a kilometer across, circled by a dyke which was piled high with regolith dust on one side. The area within the Great Wall was large enough to have an appreciable weather system: spanning enough Martian latitude for significant coriolis effects; enough longitude for diurnal warming and cooling to cause thermal currents.

He could see the nest much more clearly now; details leaping out of the haze.

Its external layout was crushingly familiar. Clavain’s side had been studying the nest from the vantage point of Deimos ever since the cease-fire. Phobos, with its lower orbit, would have been even better, of course-but there was no helping that, and perhaps the Phobos problem might actually prove useful in his negotiations with Galiana. She was somewhere in the nest, he knew: somewhere beneath the twenty varyingly sized domes emplaced within the rim, linked together by pressurized tunnels or merged at their boundaries like soap bubbles. The nest extended several tens of levels beneath the Martian surface maybe deeper.

“How many people do you think are inside?” Voi said.

“Nine hundred or so,” said Clavain. “That’s an estimate based on my experiences as a prisoner, and the hundred or so who’ve died trying to escape since. The rest, I have to say, is pretty much guesswork.”

“Our estimates aren’t dissimilar. A thousand or less here, and perhaps another three or four spread across the system in smaller nests. I know your side thinks we have better intelligence than that, but it happens not to be the case.”

“Actually, I believe you.” The shuttle’s airframe was flexing around them, morphing to a low-altitude profile with wide, bat like wings.

“I was just hoping you might have some clue as to why Galiana keeps wasting valuable lives with escape attempts.”

Voi shrugged. “Maybe to her the lives aren’t anywhere near as valuable as you’d like to think.”

“Do you honestly think that?”

“I don’t think we can begin to guess the thinking of a true hive-mind society, Clavain. Even from a Demarchist standpoint.”

There was a chirp from the console; Galiana signaling them. Clavain opened the channel allocated for Coalition-Conjoiner diplomacy.

“Nevil Clavain?” he heard.

“Yes.” He tried to sound as calm as possible. “I’m with Sandra Voi. We’re ready to land as soon as you show us where.”

“Okay,” Galiana said. “Vector your ship toward the westerly rim wall. And please, be careful.”

“Thank you. Any particular reason for the caution?”

“Just be quick about it, Nevil.”

They banked over the nest, shedding height until they were skimming only a few tens of meters above the weather worn Martian surface. A wide rectangular door had opened in the concrete dyke, revealing a hangar bay aglow with yellow lights.

“That must be where Galiana launches her shuttles from,” Clavain whispered. “We always thought there must be some kind of opening on the west side of the rim, but we never had a good view of it before.”

“Which still doesn’t tell us why she does it,” Voi said.

The console chirped again-the link poor even though they were so close. “Nose up,” Galiana said.

“You’re too low and slow. Get some altitude or the worms will lock onto you.”

“You’re telling me there are worms here?” Clavain said.

“I thought you were the worm expert, Nevil.”

He nosed the shuttle up, but fractionally too late. Ahead of them something coiled out of the ground with lightning speed, metallic jaws opening in its blunt, armored head. He recognized the type immediately:

Ouroborus class. Worms of this form still infested a hundred niches across the system. Not quite as smart as the type infesting Phobos, but still adequately dangerous.

“Shit,” Voi said, her veneer of Demarchist cool cracking for an instant.

“You said it,” Clavain answered.

The Ouroborus passed underneath and then there was a spine-jarring series of bumps as the jaws tore into the shuttle’s belly. Clavain felt the shuttle lurch down sickeningly; no longer a flying thing but an exercise in ballistics. The cool, minimalist turquoise interior shifted liquidly into an emergency configuration; damage readouts competing for attention with weapons status options. Their seats ballooned around them.

“Hold on,” he said. “We’re going down.”

Voi’s calm returned. “Do you think we can reach the rim in time?”

“Not a cat in hell’s chance.” He wrestled with the controls all the same, but it was no good. The ground was coming up fast and hard. “I wish Galiana had warned us a bit sooner…”

“I think she thought we already knew.”

They hit. It was harder than Clavain had been expecting, but the shuttle stayed in one piece and the seat cushioned him from the worst of the impact. They skidded for a few meters and then nosed up against a sandbank. Through the window Clavain saw the white worm racing toward them with undulating waves of its segmented robot body.

“I think we’re finished,” Voi said.

“Not quite,” Clavain said. “You’re not going to like this, but…Biting his tongue he brought the shuttle’s hidden weapons online. An aiming scope plunged down from the ceiling; he brought his eyes to it and locked crosshairs onto the Ouroborus. Just like old times…

“Damn you,” Voi said. “This was meant to be an unarmed mission!”

“You’re welcome to lodge a formal complaint.”

Clavain fired, the hull shaking from the recoil. Through the side window they watched the white worm blow apart into stubby segments. The parts wriggled beneath the dust.

“Good shooting,” Voi said, almost grudgingly. “Is it dead?”

“For now,” Clavain said. “It’ll take several hours for the segments to fuse back into a functional worm.”

“Good,” Voi said, pushing herself out of her seat. “But there will be a formal complaint, take my word.”

“Maybe you’d rather the worm ate us?”

“I just hate duplicity, Clavain.”

He tried the radio again. “Galiana? We’re down-the ship’s history-but we’re both unharmed.”

“Thank God.” Old verbal mannerisms died hard, even among the Conjoined. “But you can’t stay where you are. There are more worms in the area. Do you think you can make it overland to the nest?”

“It’s only two hundred meters,” Voi said. “It shouldn’t be a problem.”

Two hundred meters, yes-but two hundred meters across treacherous, potholed ground riddled with enough soft depressions to hide a dozen worms. And then they would have to climb up the rim’s side to reach the entrance to the hangar bay; ten or fifteen meters above the soil.

“Let’s hope it isn’t,” Clavain said.

He unbuckled, feeling light-headed as he stood for the first time in Martian gravity. He had adapted entirely too well to the one-gee of the Deimos ring, constructed for the comfort of Earth side tacticians.

He went to the emergency locker and found a mask which slivered eagerly across his face; another for Voi. They plugged in air-tanks and went to the shuttle’s door. This time when it sphinctered open there was a glistening membrane stretched across the doorway, a recently licensed item of Demarchist technology. Clavain pushed through the membrane and the stuff enveloped him with a wet, sucking sound. By the time he hit the dirt the membrane had hardened itself around his soles and had begun to contour itself with ribs and accordioned joints, even though it stayed transparent.

Voi came behind him, gaining her own m-suit.

They loped away from the crashed shuttle, toward the dyke. The worms would be locking onto their seismic patterns already, if there were any nearby. They might be more interested in the shuttle for now, but that was nothing they could count on. Clavain knew the behavior of worms intimately, knew the major routines which drove them; but that expertise did not guarantee his survival. It had almost failed him in Phobos.

The mask felt clammy against his face. The air at the base of the Great Wall was technically breathable even now, but there seemed no point in taking chances when speed was of the essence. His feet scuffed through the topsoil, and while he seemed to be crossing ground, the dyke obstinately refused to come any closer. It was larger than it looked from the crash; the distance further.

“Another worm,” Voi said.

White coils erupted through sand to the west. The Ouroborus was making undulating progress toward them, zig-zagging with predatory calm, knowing that it could afford to take its time. In the tunnels of Phobos, they had never had the luxury of knowing when a worm was close. They struck from ambush, quick as pythons.

“Run,” Clavain said.

Dark figures appeared in the opening high in the rimwall. A rope-ladder unfurled down the side of the structure. Clavain, making for the base of it, made no effort to quieten his footfalls. He knew that the worm almost certainly had a lock on him by now.

He looked back.

The worm paused by the downed shuttle, then smashed its diamond-jawed head into the ship, impaling the hull on its body. The worm reared up, wearing the ship like a garland. Then it shivered and the ship flew apart like a rotten carcass. The worm returned its attention to Clavain and Voi. Like a sidewinder it pulled its thirty-meter long body from the sand and rolled toward them on wheeling coils.

Clavain reached the base of the ladder.

Once, he could have ascended the ladder with his arms alone, in one-gee, but now the ladder felt alive beneath his feet. He began to climb, then realized that the ground was dropping away much faster than he was passing rungs. The Conjoiners were hauling him aloft.

He looked back in time to see Voi stumble.

“Sandra!No!”

She made to stand up, but it was too late by then. As the worm descended on her, Clavain could do nothing but turn his gaze away and pray for her death to be quick. If it had to be meaningless, he thought, at least let it be swift.

Then he started thinking about his own survival. “Faster!” he shouted, but the mask reduced his voice to a panicked muffle. He had forgotten to assign the ship’s radio frequency to the suit.

The worm thrashed against the base of the wall, then began to rear up, its maw opening beneath him; a diamond-ringed orifice like the drill of a tunnelling machine. Then something eye-hurtingly bright cut into the worm’s hide. Craning his neck, Clavain saw a group of Conjoiners kneeling over the lip of the opening, aiming guns downward. The worm writhed in intense robotic irritation. Across the sand, he could see the coils of other worms coming closer. There must have been dozens ringing the nest. No wonder Galiana’s people had made so few attempts to leave by land.

They had hauled him within ten meters of safety. The injured worm showed cybernetic workings where its hide had been flensed away by weapons impacts. Enraged, it flung itself against the rim wall, chipping off scabs of concrete the size of boulders. Clavain felt the vibration of each impact through the wall as he was dragged upward.

The worm hit again and the wall shook more violently than before. To his horror, Clavain watched one of the Conjoiners lose his footing and tumble over the edge of the rim toward him. Time oozed to a crawl.

The falling man was almost upon him. Without thinking, Clavain hugged closer to the wall, locking his limbs around the ladder. Suddenly, he had seized the man by the arm. Even in Martian gravity, even allowing for the Conjoiner’s willowy build, the impact almost sent both of them toward the Ouroborus.

Clavain felt his bones pop out of location, tearing at gristle, but he managed to keep his grip on both the Conjoiner and the ladder.

Conjoiners breathed the air at the base of the Wall without difficulty. The man wore only lightweight clothes, gray silk pajamas belted at the waist. With his sunken cheeks and bald skull, the man’s Martian physique lent him a cadaverous look. Yet somehow he had managed not to drop his gun, still holding it in his other hand.

“Let me go,” the man said.

Below, the worm inched higher despite the harm the Conjoiners had inflicted on it. “No,” Clavain said, through clenched teeth and the distorting membrane of his mask. “I’m not letting you go.”

“You’ve no option.” The man’s voice was placid. “They can’t haul both of us up fast enough, Clavain.”

Clavain looked into the Conjoiner’s face, trying to judge the man’s age. Thirty, perhaps-maybe not even that, since the cadaverous look probably made him seem older than he really was. Clavain was easily twice his age; had surely lived a richer life; had comfortably cheated death on three or four previous occasions.

“I’m the one who should die, not you.”

“No,” the Conjoiner said. “They’d find a way to blame your death on us. They’d make it a pretext for war.” Without any fuss the man pointed the gun at his own head and blew his brains out.

As much in shock as recognition that the man’s life was no longer his to save, Clavain released his grip.

The dead man tumbled down the rim wall, into the mouth of the worm which had just killed Sandra Voi.

Numb, Clavain allowed himself to be pulled to safety.

When the armored door to the hangar was shut the Conjoiners attacked his m-suit with enzymic sprays.

The sprays digested the fabric in seconds, leaving Clavain wheezing in a pool of slime. Then a pair of Conjoiners helped him unsteadily to his feet and waited patiently while he caught his breath from the mask. Through tears of exhaustion he saw that the hangar was racked full of half-assembled spacecraft; skeletal geodesic shark-shapes designed to punch out of an atmosphere, fast.

“Sandra Voi is dead,” he said, removing the mask to speak.

There was no way the Conjoiners could not have seen this for themselves, but it seemed inhuman not to acknowledge what had happened.

“I know,” Galiana said. “But at least you survived.”

He thought of the man falling into the Ouroborus. “I’m sorry about your…” But then trailed off, because for all his depth of knowledge concerning the Conjoiners, he had no idea what the appropriate term was.

“You placed your life in danger in trying to save him.”

“He didn’t have to die.”

Galiana nodded sagely. “No; in all likelihood he didn’t. But the risk to yourself was too great. You heard what he said. Your death would be made to seem our fault; justification for a pre-emptive strike against our nest. Even the Demarchists would turn against us if we were seen to murder a diplomat.”

Taking another suck from the mask, he looked into her face. He had spoken to her over low-bandwidth video-links, but only in person was it obvious that Galiana had hardly aged in fifteen years. A decade and a half of habitual expression should have engraved existing lines deeper into her face-but Conjoiners were not known for their habits of expression. Galiana had seen little sunlight in the intervening time, cooped here in the nest, and Martian gravity was much kinder to bone structure than the one-gee of Deimos. She still had the cruel beauty he remembered from his time as a prisoner. The only real evidence of aging lay in the filaments of gray threading her hair; raven-black when she had been his captor.

“Why didn’t you warn us about the worms?”

“Warn you?” For the first time something like doubt crossed her face, but it was only fleeting. “We assumed you were fully aware of the Ouroborus infestation. Those worms have been dormant-waiting-for years, but they’ve always been there. It was only when I saw how low your approach was that I realized…”

“That we might not have known?”

Worms were area-denial devices; autonomous prey-seeking mines. The war had left many pockets of the solar system still riddled with active worms. The machines were intelligent, in a one-dimensional way.

Nobody ever admitted to deploying them and it was usually impossible to convince them that the war was over and that they should quietly deactivate.

“After what happened to you in Phobos,” Galiana said, “I assumed there was nothing you needed to be taught about worms.”

He never liked thinking about Phobos: the pain was still too deeply engraved. But if it had not been for the injuries he had sustained there he would never have been sent to Deimos to recuperate; would never have been recruited into his brother’s intelligence wing to study the Conjoiners. Out of that phase of deep immersion in everything concerning the enemy had come his peacetime role as negotiator-and now diplomat-on the eve of another war. Everything was circular, ultimately. And now Phobos was central to his thinking because he saw it as a way out of the impasse-maybe the last chance for peace. But it was too soon to put his idea to Galiana. He was not even sure the mission could still continue, after what had happened.

“We’re safe now, I take it?”

“Yes; we can repair the damage to the dyke. Mostly, we can ignore their presence.”

“We should have been warned. Look, I need to talk to my brother.”

“Warren? Of course. It’s easily arranged.”

They walked out of the hangar; away from the half-assembled ships. Somewhere deeper in the nest, Clavain knew, was a factory where the components for the ships were made, mined out of Mars or winnowed from the fabric of the nest. The Conjoiners managed to launch one every six weeks or so; had been doing so for six months. Not one of the ships had ever managed to escape the Martian atmosphere before being shot down…but sooner or later he would have to ask Galiana why she persisted with this provocative folly.

Now, though, was not the time-even if, by Warren’s estimate, he only had three days before Galiana’s next provocation.

The air elsewhere in the nest was thicker and warmer than in the hangar, which meant he could dispense with the mask. Galiana took him down a short, gray-walled, metallic corridor which ended in a circular room containing a console. He recognized the room from the times he had spoken to Galiana from Deimos. Galiana showed him how to use the system then left him in privacy while he established a connection with Deimos.

Warren’s face soon appeared on a screen, thick with pixels like an impressionist portrait. Conjoiners were only allowed to send kilobytes a second to other parts of the system. Much of that bandwidth was now being sucked up by this one video link.

“You’ve heard, I take it,” Clavain said.

Warren nodded, his face ashen. “We had a pretty good view from orbit, of course. Enough to see that Voi didn’t make it. Poor woman. We were reasonably sure you survived, but it’s good to have it confirmed.”

“Do you want me to abandon the mission?”

Warren’s hesitation was more than just time-lag. “No…I thought about it, of course, and high command agrees with me. Voi’s death was tragic-no escaping that. But she was only along as a neutral observer.

If Galiana consents for you to stay, I suggest you do so.”

“But you still say I only have three days?”

“That’s up to Galiana, isn’t it? Have you learned much?”

“You must be kidding. I’ve seen shuttles ready for launch, that’s all. I haven’t raised the Phobos proposal, either. The timing wasn’t exactly ideal, after what happened to Voi.”

“Yes. If only we’d known about that Ouroborus infestation.”

Clavain leaned closer to the screen. “Yes. Why the hell didn’t we? Galiana assumed that we would, and I don’t blame her for that. We’ve had the nest under constant surveillance for fifteen years. Surely in all that time we’d have seen evidence of the worms?”

“You’d have thought so, wouldn’t you?”

“Meaning what?”

“Meaning, maybe the worms weren’t always there.”

Conscious that there could be nothing private about this conversation-but unwilling to drop the thread-Clavain said: “You think the Conjoiners put them there to ambush us?”

“I’m saying we shouldn’t disregard any possibility, no matter how unpalatable.”

“Galiana would never do something like that.”

“No, I wouldn’t.” She had just stepped back into the room. “And I’m disappointed that you’d even debate the possibility.”

Clavain terminated the link with Deimos. “Eavesdropping’s not a very nice habit, you know.”

“What did you expect me to do?”

“Show some trust? Or is that too much of a stretch?”

“I never had to trust you when you were my prisoner,” Galiana said. “That made our relationship infinitely simpler. Our roles were completely defined.”

“And now? If you distrust me so completely, why did you ever agree to my visit? Plenty of other specialists could have come in my place. You could even have refused any dialogue.”

“Voi’s people pressured us to allow your visit,” Galiana said. “Just as they pressured your side into delaying hostilities a little longer.”

“Is that all?”

She hesitated slightly now. “I…knew you.”

“Knew me? Is that how you sum up a year of imprisonment? What about the thousands of conversations we had; the times when we put aside our differences to talk about something other than the damned war?

You kept me sane, Galiana. I’ve never forgotten that. It’s why I’ve risked my life to come here and talk you out of another provocation.”

“It’s completely different now.”

“Of course!” He forced himself not to shout. “Of course it’s different. But not fundamentally. We can still build on that bond of trust and find a way out of this crisis.”

“But does your side really want a way out of it?”

He did not answer her immediately; wary of what the truth might mean. “I’m not sure. But I’m also not sure you do, or else you wouldn’t keep pushing your luck.” Something snapped inside him and he asked the question he had meant to ask in a million better ways. “Why do you keep doing it, Galiana? Why do you keep launching those ships when you know they’ll be shot down as soon as they leave the nest?”

Her eyes locked onto his own, unflinchingly. “Because we can. Because sooner or later one will succeed.”

Clavain nodded. It was exactly the sort of thing he had feared she would say.

She led him through more gray-walled corridors, descending several levels deeper into the nest. Light poured from snaking strips embedded into the walls like arteries. It was possible that the snaking design was decorative, but Clavain thought it much more likely that the strips had simply grown that way, expressing biological algorithms. There was no evidence that the Conjoiners had attempted to enliven their surroundings; to render them in any sense human.

“It’s a terrible risk you’re running,” Clavain said.

“And the status quo is intolerable. I’ve every desire to avoid another war, but if it came to one, we’d at least have the chance to break these shackles.”

“If you didn’t get exterminated first…”

“We’d avoid that. In any case, fear plays no part in our thinking. You saw the man accept his fate on the dyke, when he understood that your death would harm us more than his own. He altered his state of mind to one of total acceptance.”

“Fine. That makes it all right, then.”

She halted. They were alone in one of the snakingly lit corridors; he had seen no other Conjoiners since the hangar. “It’s not that we regard individual lives as worthless, any more than you would willingly sacrifice a limb. But now that we’re part of something larger…”

“Transenlightenment, you mean?”

It was the Conjoiners’ term for the state of neural communion they shared, mediated by the machines swarming in their skulls. Whereas Demarchists used implants to facilitate real time democracy, Conjoiners used them to share sensory data, memories-even conscious thought itself. That was what had precipitated the war. Back in 2190 half of humanity had been hooked into the system-wide data nets via neural implants. Then the Conjoiner experiments had exceeded some threshold, unleashing a transforming virus into the nets. Implants had begun to change, infecting millions of minds with the templates of Conjoiner thought. Instantly the infected had become the enemy. Earth and the other inner planets had always been more conservative, preferring to access the nets via traditional media.

Once they saw communities on Mars and in the asteroid belts fall prey to the Conjoiner phenomenon, the Coalition powers hurriedly pooled their resources to prevent the spread reaching their own states. The Demarchists, out around the gas giants, had managed to get firewalls up before many of their habitats were lost. They had chosen neutrality while the Coalition tried to contain-some said sterilize-zones of Conjoiner takeover. Within three years-after some of the bloodiest battles in human experience-the Conjoiners had been pushed back to a clutch of hideaways dotted around the system. Yet all along they professed a kind of puzzled bemusement that their spread was being resisted. After all, no one who had been assimilated seemed to regret it. Quite the contrary. The few prisoners whom the Conjoiners had reluctantly returned to their pre-infection state had sought every means to return to the fold. Some had even chosen suicide rather than be denied Transenlightenment. Like acolytes given a vision of heaven, they devoted their entire waking existence to the search for another glimpse.

“Transenlightenment blurs our sense of self,” Galiana said. “When the man elected to die, the sacrifice was not absolute for him. He understood that much of what he was had already achieved preservation among the rest of us.”

“But he was just one man. What about the hundred lives you’ve thrown away with your escape attempts? We know-we’ve counted the bodies.”

“Replacements can always be cloned.”

Clavain hoped that he hid his disgust satisfactorily. Among his people the very notion of cloning was an unspeakable atrocity; redolent with horror. To Galiana it would be just another technique in her arsenal.

“But you don’t clone, do you? And you’re losing people. We thought there would be nine hundred of you in this nest, but that was a gross overestimate, wasn’t it?”

“You haven’t seen much yet,” Galiana said.

“No, but this place smells deserted. You can’t hide absence, Galiana. I bet there aren’t more than a hundred of you left here.”

“You’re wrong,” Galiana said. “We have cloning technology, but we’ve hardly ever used it. What would be the point? We don’t aspire to genetic unity, no matter what your propagandists think. The pursuit of optima leads only to local minima. We honor our errors. We actively seek persistent disequilibrium.”

“Right.” The last thing he needed now was a dose of Conjoiner rhetoric. “So where the hell is everyone?”

In a while he had part of the answer, if not the whole of it. At the end of the maze of corridors-far under Mars now-Galiana brought him to a nursery.

It was shockingly unlike his expectations. Not only did it not match what he had imagined from the vantage point of Deimos, but it jarred against his predictions based on what he had seen so far of the nest. In Deimos, he had assumed a Conjoiner nursery would be a place of grim medical efficiency; all gleaming machines with babies plugged in like peripherals, like a monstrously productive doll factory.

Within the nest, he had revised his model to allow for the depleted numbers of Conjoiners. If there was a nursery, it was obviously not very productive. Fewer babies, then-but still a vision of hulking gray machines, bathed in snaking light.

The nursery was nothing like that.

The huge room Galiana showed him was almost painfully bright and cheerful; a child’s fantasy of friendly shapes and primary colors. The walls and ceiling projected a holographic sky: infinite blue and billowing clouds of heavenly white. The floor was an undulating mat of synthetic grass forming hillocks and meadows. There were banks of flowers and forests of bonsai trees. There were robot animals: fabulous birds and rabbits just slightly too anthropomorphic to fool Clavain. They were like the animals in children’s books; big-eyed and happy-looking. Toys were scattered on the grass.

And there were children. They numbered between forty and fifty; spanning by his estimate ages from a few months to six or seven standard years. Some were crawling among the rabbits; other, older children were gathered around tree stumps whose sheered-off surfaces flickered rapidly with images, underlighting their faces. They were talking among themselves, giggling or singing. He counted perhaps half a dozen adult Conjoiners kneeling among the children. The children’s clothes were a headache of bright, clashing colors and patterns. The Conjoiners crouched among them like ravens. Yet the children seemed at ease with them, listening attentively when the adults had something to say.

“This isn’t what you thought it would be like, is it?”

“No…not at all.” There seemed no point lying to her. “We thought you’d raise your young in a simplified version of the machine-generated environment you experience.”

“In the early days that’s more or less what we did.” Subtly, Galiana’s tone of voice had changed. “Do you know why chimpanzees are less intelligent than humans?”

He blinked at the change of tack. “I don’t know-are their brains smaller?”

“Yes-but a dolphin’s brain is larger, and they’re scarcely more intelligent than dogs.” Galiana stooped next to a vacant tree stump. Without seeming to do anything, she made a diagram of mammal brain anatomies appear on the trunk’s upper surface, then sketched her finger across the relevant parts. “It’s not overall brain volume that counts so much as the developmental history. The difference in brain volume between a neonatal chimp and an adult is only about twenty percent. By the time the chimp receives any data from beyond the womb, there’s almost no plasticity left to use. Similarly, dolphins are born with almost their complete repertoire of adult behavior already hardwired. A human brain, on the other hand, keeps growing through years of learning. We inverted that thinking. If data received during post-natal growth was so crucial to intelligence, perhaps we could boost our intelligence even further by intervening during the earliest phases of brain development.”

“In the womb?”

“Yes.” Now she made the tree-trunk show a human embryo running through cycles of cell-division, until the faint fold of a rudimentary spinal nerve began to form, nubbed with the tiniest of emergent minds.

Droves of subcellular machines swarmed in, invading the nascent nervous system. Then the embryo’s development slammed forward, until Clavain was looking at an unborn human baby.

“What happened?”

“It was a grave error,” Galiana said. “Instead of enhancing normal neural development, we impaired it terribly. All we ended up with were various manifestations of savant syndrome.”

Clavain looked around him. “Then you let these kids develop normally?”

“More or less. There’s no family structure, of course, but then again there are plenty of human and primate societies where the family is less important in child development than the cohort group. So far we haven’t seen any pathologies.”

Clavain watched as one of the older children was escorted out of the grassy room, through a door in the sky. When the Conjoiner reached the door the child hesitated, tugging against the man’s gentle insistence.

The child looked back for a moment, then followed the man through the gap.

“Where’s that child going?”

“To the next stage of its development.”

Clavain wondered what were the chances of him seeing the nursery just as one of the children was being promoted. Small, he judged-unless there was a crash program to rush as many of them through as quickly as possible. As he thought about this, Galiana took him into another part of the nursery. While this room was smaller and dourer it was still more colorful than any other part of the nest he had seen before the grassy room. The walls were a mosaic of crowded, intermingling displays, teeming with moving images and rapidly scrolling text. He saw a herd of zebra stampeding through the core of a neutron star. Elsewhere an octopus squirted ink at the face of a twentieth-century despot. Other display facets rose from the floor like Japanese paper screens, flooded with data. Children-up to early teenagers-sat on soft black toadstools next to the screens in little groups, debating. A few musical instruments lay around unused: holoclaviers and air-guitars. Some of the children had gray bands around their eyes and were poking their fingers through the interstices of abstract structures, exploring the dragon-infested waters of mathematical space. Cla-vain could see what they were manipulating on the flat screens: shapes that made his head hurt even in two dimensions.

“They’re nearly there,” Clavain said. “The machines are outside their heads, but not for long. When does it happen?”

“Soon; very soon.”

“You’re rushing them, aren’t you? Trying to get as many children Conjoined as you can. What are you planning?”

“Something…has arisen, that’s all. The timing of your arrival is either very bad or very fortunate, depending on your point of view.” Before he could query her, Galiana added: “Clavain; I want you to meet someone.”

“Who?”

“Someone very precious to us.”

She took him through a series of child-proof doors until they reached a small circular room. The walls and ceiling were veined gray; tranquil after what he had seen in the last place. A child sat cross-legged on the floor in the middle of the room. Clavain estimated the girl’s age as ten standard years-perhaps fractionally older. But she did not respond to Clavain’s presence in any way an adult, or even a normal child, would have. She just kept on doing the thing she had been doing when they stepped inside, as if they were not really present at all. It was not at all clear what she was doing. Her hands moved before her in slow, precise gestures. It was as if she were playing a holoclavier or working a phantom puppet show. Now and then she would pivot around until she was facing another direction and carry on doing the hand movements.

“Her name’s Felka,” Galiana said.

“Hello, Felka…” He waited for a response, but none came. “I can see there’s something wrong with her.”

“She was one of the savants. Felka developed with machines in her head. She was the last to be born before we realized our failure.”

Something about Felka disturbed him. Perhaps it was the way she carried on regardless, engrossed in an activity to which she seemed to attribute the utmost significance, yet which had to be without any sane purpose.

“She doesn’t seem aware of us.”

“Her deficits are severe,” Galiana said. “She has no interest in other human beings. She has prosopagnosia; the inability to distinguish faces. We all seem alike to her. Can you imagine something more strange than that?”

He tried, and failed. Life from Felka’s viewpoint must have been a nightmarish thing, surrounded by identical clones whose inner lives she could not begin to grasp. No wonder she seemed so engrossed in her game.

“Why is she so precious to you?” Clavain asked, not really wanting to know the answer.

“She’s keeping us alive,” Galiana said.

Of course, he asked Galiana what she meant by that. Galiana’s only response was to tell him that he was not yet ready to be shown the answer.

“And what exactly would it take for me to reach that stage?”

“A simple procedure.”

Oh yes, he understood that part well enough. Just a few machines in the right parts of his brain and the truth could be his. Politely, doing his best to mask his distaste, Clavain declined. Fortunately, Galiana did not press the point, for the time had arrived for the meeting he had been promised before his arrival on Mars.

He watched a subset of the nest file into the conference room. Galiana was their leader only inasmuch as she had founded the lab here from which the original experiment had sprung and was accorded some respect deriving from seniority. She was also the most obvious spokesperson among them. They all had areas of expertise which could not be easily shared among other Conjoined; very distinct from the hive-mind of identical clones which still figured in the Coalition’s propaganda. If the nest was in any way like an ant colony, then it was an ant colony in which every ant fulfilled a distinct role from all the others.

Naturally, no individual could be solely entrusted with a particular skill essential to the nest-that would have been dangerous over-specialization-but neither had individuality been completely subsumed into the group mind.

The conference room must have dated back to the days when the nest was a research outpost, or even earlier, when it was some kind of mining base in the early 2100s. It was much too big for the dour handful of Conjoiners who stood around the main table. Tactical readouts around the table showed the build-up of strike forces above the Martian exclusion zone; probable drop trajectories for ground-force deployment.

“Nevil Clavain,” Galiana said, introducing him to the others. Everyone sat down. “I’m just sorry that Sandra Voi can’t be with us now. We all feel the tragedy of her death. But perhaps out of this terrible event we can find some common ground. Nevil; before you came here you told us you had a proposal for a peaceful resolution to the crisis.”

“I’d really like to hear it,” one of the others murmured audibly.

Clavain’s throat was dry. Diplomatically, this was quicksand. “My proposal concerns Phobos…”

“Go on.”

“I was injured there,” he said. “Very badly. Our attempt to clean out the worm infestation failed and I lost some good friends. That makes it personal between me and the worms. But I’d accept anyone’s help to finish them off.”

Galiana glanced quickly at her compatriots before answering. “A joint assault operation?”

“It could work.”

“Yes…” Galiana seemed lost momentarily. “I suppose it could be a way out of the impasse. Our own attempt failed too-and the interdiction’s stopped us from trying again.” Again, she seemed to fall into reverie. “But who would really benefit from the flushing out of Phobos? We’d still be quarantined here.”

Clavain leaned forward. “A cooperative gesture might be exactly the thing to lead to a relaxation in the terms of the interdiction. But don’t think of it in those terms. Think instead of reducing the current threat from the worms.”

“Threat?”

Clavain nodded. “It’s possible that you haven’t noticed.” He leaned forward, elbows on the table.

“We’re concerned about the Phobos worms. They’ve begun altering the moon’s orbit. The shift is tiny at the moment, but too large to be anything other than deliberate.”

Galiana looked away from him for an instant, as if weighing her options. Then said: “We were aware of this, but you weren’t to know that.”

Gratitude?

He had assumed the worms’ activity could not have escaped Galiana. “We’ve seen odd behavior from other worm infestations across the system; things that begin to look like emergent intelligence. But never anything this purposeful. This infestation must have come from a batch with some subroutines we never even guessed about. Do you have any ideas about what they might be up to?”

Again, there was the briefest of hesitations, as if she was communing with her compatriots for the right response. Then she nodded toward a male Conjoiner sitting opposite her, Clavain guessing that the gesture was entirely for his benefit. His hair was black and curly; his face as smooth and untroubled by expression as Galiana’s, with something of the same beautifully symmetrical bone structure.

“This is Remontoire,” said Galiana. “He’s our specialist on the Phobos situation.”

Remontoire nodded politely. “In answer to your question, we currently have no viable theories as to what they’re doing, but we do know one thing. They’re raising the apocentre of the moon’s orbit.” Apocentre, Clavain knew, was the Martian equivalent of apogee for an object orbiting Earth: the point of highest altitude in an elliptical orbit. Remontoire continued, his voice as preternaturally calm as a parent reading slowly to a child. “The natural orbit of Phobos is actually inside the Roche limit for a gravitationally bound moon; Phobos is raising a tidal bulge on Mars but, because of friction, the bulge can’t quite keep up with Phobos. It’s causing Phobos to spiral slowly closer to Mars, by about two meters a century. In a few tens of millions of years, what’s left of the moon will crash into Mars.”

“You think the worms are elevating the orbit to avoid a cataclysm so far in the future?”

“I don’t know,” Remontoire said. “I suppose the orbital alterations could also be a byproduct of some less meaningful worm activity.”

“I agree,” Clavain said. “But the danger remains. If the worms can elevate the moon’s apocentre-even accidentally-we can assume they also have the means to lower its pericentre. They could drop Phobos on top of your nest. Does that scare you sufficiently that you’d consider cooperation with the Coalition?”

Galiana steepled her fingers before her face; a human gesture of deep concentration which her time as a Conjoiner had not quite eroded. Clavain could almost feel the web of thought looming in the room; ghostly strands of cognition reaching between each Conjoiner at the table, and beyond into the nest proper.

“A winning team, is that your idea?”

“It’s got to be better than war,” Clavain said. “Hasn’t it?”

Galiana might have been about to answer him when her face grew troubled. Clavain saw the wave of discomposure sweep over the others almost simultaneously. Something told him that it was nothing to do with his proposal.

Around the table, half the display facets switched automatically over to another channel. The face that Clavain was looking at was much like his own, except that the face on the screen was missing an eye. It was his brother. Warren was overlaid with the official insignia of the Coalition and a dozen system-wide media cartels.

He was in the middle of a speech. “…express my shock,” Warren said. “Or, for that matter, my outrage.

It’s not just that they’ve murdered a valued colleague and deeply experienced member of my team.

They’ve murdered my brother.”

Clavain felt the deepest of chills. “What is this?”

“A live transmission from Deimos,” Galiana breathed. “It’s going out to all the nets; right out to the trans-Pluto habitats.”

“What they did was an act of unspeakable treachery,” Warren said. “Nothing less than the premeditated, cold-blooded murder of a peace envoy.” And then a video clip sprang up to replace Warren. The image must have been snapped from Deimos or one of the interdiction satellites. It showed Clavain’s shuttle, lying in the dust close to the dyke. He watched the Ouroborus destroy the shuttle, then saw the image zoom in on himself and Voi, running for sanctuary. The Ouroborus took Voi. But this time there was no ladder lowered down for him. Instead, he saw weapon-beams scythe out from the nest toward him, knocking him to the ground. Horribly wounded, he tried to get up, to crawl a few inches nearer to his tormentors, but the worm was already upon him.

He watched himself get eaten.

Warren was back again. “The worms around the nest were a Conjoiner trap. My brother’s death must have been planned days-maybe even weeks-in advance.” His face glistened with a wave of military composure. “There can only be one outcome from such an action-something the Conjoiners must have well understood. For months they’ve been goading us toward hostile action.” He paused, then nodded at an unseen audience. “Well now they’re going to get it. In fact, our response has already commenced.”

“Dear God, no,” Clavain said, but the evidence was all there now; all around the table he could see the updating orbital spread of the Coalition’s dropships, knifing down toward Mars.

“I think it’s war,” Galiana said.

Conjoiners stormed onto the roof of the nest, taking up defensive positions around the domes and the dyke’s edge. Most of them carried the same guns which they had used against the Ouroborus. Smaller numbers were setting up automatic cannon on tripods. One or two were manhandling large anti-assault weapons into position. Most of it was war-surplus. Fifteen years ago the Conjoiners had avoided extinction by deploying weapons of awesome ferocity-but those ship-to-ship armaments were too simply too destructive to use against a nearby foe. Now it would be more visceral; closer to the primal templates of combat, and none of what the Conjoiners were marshalling would be much use against the kind of assault Warren had prepared, Clavain knew. They could slow an attack, but not much more than that.

Galiana had given him another breather mask, made him don lightweight chameleoflage armor, and then forced him to carry one of the smaller guns. The gun felt alien in his hands; something he had never expected to carry again. The only possible justification for carrying it was to use it against his brother’s forces-against his own side.

Could he do that?

It was clear that Warren had betrayed him; he had surely been aware of the worms around the nest. So his brother was capable not just of contempt, but of treacherous murder. For the first time, Clavain felt genuine hatred for Warren. He must have hoped that the worms would destroy the shuttle completely and kill Clavain and Voi in the process. It must have pained him to see Clavain make it to the dyke…pained him even more when Clavain called to talk about the tragedy. But Warren’s larger plan had not been affected. The diplomatic link between the nest and Deimos was secure-even the Demarchists had no immediate access to it. So Clavain’s call from the surface could be quietly ignored; spysat imagery doctored to make it seem that he had never reached the dyke…had in fact been repelled by Conjoiner treachery. Inevitably the Demarchists would unravel the deception given time…but if Warren’s plan succeeded, they would all be embroiled in war long before then. That, thought Clavain, was all that Warren had ever wanted.

Two brothers, Clavain thought. In many ways so alike. Both had embraced war once, but like a fickle lover Clavain had wearied of its glories. He had not even been injured as severely as Warren…but perhaps that was the point, too. Warren needed another war to avenge what one had stolen from him.

Clavain despised and pitied him in equal measure.

He searched for the safety clip on the gun. The rifle, now that he studied it more closely, was not all that different from those he had used during the war. The readout said the ammo-cell was fully charged.

He looked into the sky.

The attack wave broke orbit hard and steep above the Wall; five hundred fire-balls screeching toward the nest. The insertion scorched inches of ablative armor from most of the ships; fried a few others which came in just fractionally too hard. Clavain knew that was how it was happening: he had studied possible attack scenarios for years, the range of outcomes burned indelibly into his memory.

The anti-assault guns were already working-locking onto the plasma trails as they flowered overhead, swinging down to find the tiny spark of heat at the head, computing refraction paths for laser pulses, spitting death into the sky. The unlucky ships flared a white that hurt the back of the eye and rained down in a billion dulling sparks. A dozen-then a dozen more. Maybe fifty in total before the guns could no longer acquire targets. It was nowhere near enough. Clavain’s memory of the simulations told him that at least four hundred units of the attack wave would survive both re-entry and the Conjoiner’s heavy defenses.

Nothing that Galiana could do would make any difference.

And that had always been the paradox. Galiana was capable of running the same simulations. She must always have known that her provocations would bring down something she could never hope to defeat.

Something that was always going to destroy her.

The surviving members of the wave were levelling out now, commencing long, ground-hugging runs from all directions. Cocooned in their dropships, the soldiers would be suffering punishing gee-loads…but it was nothing they were not engineered to withstand; half their cardiovascular systems were augmented by the only kinds of implant the Coalition tolerated.

The first of the wave came arcing in at supersonic speeds. All around, worms struggled to snatch them out of the sky, but mostly they were too slow to catch the dropships. Galiana’s people manned their cannon positions and did their best to fend off what they could. Clavain clutched his gun, not firing yet.

Best to save his ammo-cell power for a target he stood a chance of injuring.

Above, the first dropships made hairpin turns, nosing suicidally down toward the nest. Then they fractured cleanly apart, revealing falling pilots clad in bulbous armor. Just before the moment of impact each pilot exploded into a mass of black shock-absorbing balloons, looking something like a blackberry, bouncing across the nest before the balloons deflated just as swiftly and the pilot was left standing on the ground. By then the pilot-now properly a soldier-would have a comprehensive computer-generated map of the nest’s nooks and crannies; enemy positions graphed in real time from the down-looking spysats.

Clavain fell behind the curve of a dome before the nearest soldier got a lock onto him. The firefight was beginning now. He had to hand it to Galiana’s people-they were fighting like devils. And they were at least as well coordinated as the attackers. But their weapons and armor were simply inadequate.

Chameleoflage was only truly effective against a solitary enemy, or a massed enemy moving in from a common direction. With Coalition forces surrounding him, Clavain’s suit was going crazy to trying to match itself against every background, like a chameleon in a house of mirrors.

The sky overhead looked strange now-darkening purple. And the purple was spreading in a mist across the nest. Galiana had deployed some kind of chemical smoke screen: infrared and optically opaque, he guessed. It would occlude the spysats and might be primed to adhere only to enemy chameleoflage. That had never been in Warren’s simulations. Galiana had just given herself the slightest of edges.

A soldier stepped out of the mist, the obscene darkness of a gun muzzle trained on Clavain. His chameleoflage armor was dappled with vivid purple patches, ruining its stealthiness. The man fired, but his discharge wasted itself against Clavain’s armor. Clavain returned the compliment, dropping his compatriot. What he had done, he thought, was not technically treason. Not yet. All he had done was act in self-preservation.

The man was wounded, but not yet dead. Clavain stepped through the purple haze and knelt down beside the soldier. He tried not to look at the man’s wound.

“Can you hear me?” he said. There was no answer from the man, but beneath his visor, Clavain thought he saw the man’s lips shape a sound. The man was just a kid-hardly old enough to remember much of the last war. “There’s something you have to know,” Clavain continued. “Do you realize who I am?” He wondered how recognizable he was, under the breather mask. Then something made him relent. He could tell the man he was Nevil Clavain-but what would that achieve? The soldier would be dead in minutes; maybe sooner than that. Nothing would be served by the soldier knowing that the basis for his attack was a lie; that he would not in fact be laying down his life for a just cause. The universe could be spared a single callous act.

“It’s all right,” Clavain said, turning away from his victim.

And then moved deeper into the nest, to see who else he could kill before the odds took him.

But the odds never did.

“You always were lucky,” Galiana said, leaning over him. They were somewhere underground again-deep in the nest. A medical area, by the look of things. He was on a bed, fully clothed apart from the outer layer of chameleoflage armor. The room was gray and kettle-shaped, ringed by a circular balcony.

“What happened?”

“You took a head wound, but you’ll survive.”

He groped for the right question. “What about Warren’s attack?”

“We endured three waves. We took casualties, of course.”

Around the circumference of the balcony were thirty or so gray couches, slightly recessed into archways studded with gray medical equipment. They were all occupied. There were more Conjoiners in this room than he had seen so far in one place. Some of them looked very close to death.

Clavain reached up and examined his head, gingerly. There was some dried blood on the scalp, matted with his hair; some numbness, but it could have been a lot worse. He felt normal-no memory drop-outs or aphasia. When he made to stand from the bed, his body obeyed his will with only a tinge of dizziness.

“Warren won’t stop at just three waves, Galiana.”

“I know.” She paused. “We know there’ll be more.”

He walked to the railing on the inner side of the balcony and looked over the edge. He had expected to see something-some chunk of incomprehensible surgical equipment, perhaps-but the middle of the room was only an empty, smooth-walled, gray pit. He shivered. The air was colder than any part of the nest he had visited so far, with a medicinal tang which reminded him of the convalescence ward on Deimos. What made him shiver even more was the realization that some of the injured-some of the dead-were barely older than the children he had visited only hours ago. Perhaps some of them were those children, conscripted from the nursery since his visit, uploaded with fighting reflexes through their new implants.

“What are you going to do? You know you can’t win. Warren lost only a tiny fraction of his available force in those waves. You look like you’ve lost half your nest.”

“It’s much worse than that,” Galiana said.

“What do you mean?”

“You’re not quite ready yet. But I can show you in a moment.”

He felt colder than ever now. “What do you mean, not quite ready?”

Galiana looked deep into his eyes now. “You took a serious head wound, Cla-vain. The entry wound was small, but the internal bleeding…it would have killed you, had we not intervened.” Before he could ask the inevitable question she answered it for him. “We injected a small cluster of medichines into your head. They undid the damage very easily. But it seemed provident to allow them to grow.”

“You’ve put replicators in my head?”

“You needn’t sound so horrified. They’re already growing-spreading out and interfacing with your existing neural circuitry-but the total volume of glial mass that they will consume is tiny: only a few cubic millimeters in total, across your entire brain.”

He wondered if she was calling his bluff. “I don’t feel anything.”

“You won’t-not for a minute or so.” Now she pointed into the empty pit in the middle of the room.

“Stand here and look into the air.”

“There’s nothing there.”

But as soon as he had spoken, he knew he was wrong. There was something in the pit. He blinked and directed his attention somewhere else, but when he returned his gaze to the pit, the thing he imagined he had seen-milky, spectral-was still there, and becoming sharper and brighter by the second. It was a three-dimensional structure, as complex as an exercise in protein-folding. A tangle of loops and connecting branches and nodes and tunnels, embedded in a ghostly red matrix.

Suddenly he saw it for what it was: a map of the nest, dug into Mars. Just as the Coalition had suspected, the base was deeper than the original structure; far more extensive, reaching deeper down but much further out than anyone had imagined. Clavain made a mental effort to retain some of what he was seeing in his mind, the intelligence-gathering reflex stronger than the conscious knowledge that he would never see Deimos again.

“The medichines in your brain have interfaced with your visual cortex,” Galiana said. “That’s the first step on the road to Transenlightenment. Now you’re privy to the machine-generated imagery encoded by the fields through which we move-most of it, anyway.”

“Tell me this wasn’t planned, Galiana. Tell me you weren’t intending to put machines in me at the first opportunity.”

“No; I wasn’t planning it. But nor was I going to let your phobias stop me from saving your life.”

The image grew in complexity. Glowing nodes of light appeared in the tunnels, some moving slowly through the network.

“What are they?”

“You’re seeing the locations of the Conjoiners,” Galiana said. “Are there as many as you imagined?”

Clavain judged that there were no more than seventy lights in the whole complex now. He searched for a cluster which would identify the room where he stood. There: twenty-odd bright lights, accompanied by one much fainter. Himself, of course. There were few people near the top of the nest-the attack must have collapsed half the tunnels, or maybe Galiana had deliberately sealed entrances herself.

“Where is everyone? Where are the children?”

“Most of the children are gone now.” She paused. “You were right to guess that we were rushing them to Transenlightenment, Clavain.”

“Why?”

“Because it’s the only way out of here.”

The image changed again. Now each of the bright lights was connected to another by a shimmering filament. The topology of the network was constantly shifting, like a pattern seen in a kaleidoscope.

Occasionally, too swiftly for Clavain to be sure, it shifted toward a mandala of elusive symmetry, only to dissolve into the flickering chaos of the ever-changing network. He studied Galiana’s node and saw that-even as she was speaking to him-her mind was in constant rapport with the rest of the nest.

Now something very bright appeared in the middle of the image, like a tiny star, against which the shimmering network paled almost to invisibility. “The network is abstracted now,” Galiana said. “The bright light represents its totality: the unity of Transenlightenment. Watch.”

He watched. The bright light-beautiful and alluring as anything Clavain had ever imagined-was extending a ray toward the isolated node which represented himself. The ray was extending itself through the map, coming closer by the second.

“The new structures in your mind are nearing maturity,” Galiana said. “When the ray touches you, you will experience partial integration with the rest of us. Prepare yourself, Nevil.”

Her words were unnecessary. His fingers were already clenched sweating on the railing as the light inched closer and engulfed his node.

“I should hate you for this,” Clavain said.

“Why don’t you? Hate’s always the easier option.”

“Because…” Because it made no difference now. His old life was over. He reached out for Galiana, needing some anchor against what was about to hit him. Galiana squeezed his hand and an instant later he knew something of Transenlightenment. The experience was shocking; not because it was painful or fearful, but because it was profoundly and totally new. He was literally thinking in ways that had not been possible microseconds earlier.

Afterward, when Clavain tried to imagine how he might describe it, he found that words were never going to be adequate for the task. And that was no surprise: evolution had shaped language to convey many concepts, but going from a single to a networked topology of self was not among them. But if he could not convey the core of the experience, he could at least skirt its essence with metaphor. It was like standing on the shore of an ocean, being engulfed by a wave taller than himself. For a moment he sought the surface; tried to keep the water from his lungs. But there happened not to be a surface. What had consumed him extended infinitely in all directions. He could only submit to it. Yet as the moments slipped by it turned from something terrifying in its unfamiliarity to something he could begin to adapt to; something that even began in the tiniest way to seem comforting. Even then he glimpsed that it was only a shadow of what Galiana was experiencing every instant of her life.

“All right,” Galiana said. “That’s enough for now.”

The fullness of Transenlightenment retreated, like a fading vision of Godhead. What he was left with was purely sensory; no longer any direct rapport with the others. His state of mind came crashing back to normality.

“Are you all right, Nevil?”

“Yes…” His mouth was dry. “Yes; I think so.”

“Look around you.”

He did.

The room had changed completely. So had everyone in it.

His head reeling, Clavain walked in light. The formerly gray walls oozed beguiling patterns; as if a dark forest had suddenly become enchanted. Information hung in veils in the air; icons and diagrams and numbers clustering around the beds of the injured, thinning out into the general space like fantastically delicate neon sculptures. As he walked toward the icons they darted out of his way, mocking him like schools of brilliant fish. Sometimes they seemed to sing, or tickle the back of his nose with half-familiar smells.

“You can perceive things now,” Galiana said. “But none of it will mean much to you. You’d need years of education, or deeper neural machinery for that-building cognitive layers. We read all this almost subliminally.”

Galiana was dressed differently now. He could still see the vague shape of her gray outfit, but layered around it were billowing skeins of light, unravelling at their edges into chains of Boolean logic. Icons danced in her hair like angels. He could see, faintly, the web of thought linking her with the other Conjoiners.

She was inhumanly beautiful.

“You said things were much worse,” Clavain said. “Are you ready to show me now?”

She took him to see Felka again, passing on the way through deserted nursery rooms, populated now only by bewildered mechanical animals. Felka was the only child left in the nursery.

Clavain had been deeply disturbed by Felka when he had seen her before, but not for any reason he could easily express. Something about the purposefulness of what she did; performed with ferocious concentration, as if the fate of creation hung on the outcome of her game. Felka and her surroundings had not changed at all since his visit. The room was still austere to the point of oppressiveness. Felka looked the same. In every respect it was as if only an instant had passed since their meeting; as if the onset of war and the assaults against the nest-the battle of which this was only an interlude-were only figments from someone else’s troubling dream; nothing that need concern Felka in her devotion to the task at hand.

And what the task was awed Clavain.

Before he had watched her make strange gestures in front of her. Now the machines in his head revealed the purpose that those gestures served. Around Felka-cordoning her like a barricade-was a ghostly representation of the Great Wall.

She was doing something to it.

It was not a scale representation, Clavain knew. The Wall looked much higher here in relation to its diameter. And the surface was not the nearly invisible membrane of the real thing, but something like etched glass. The etchwork was a filigree of lines and junctions, descending down to smaller and smaller scales in fractal steps, until the blur of detail was too fine for his eyes to discriminate. It was shifting and altering color, and Felka was responding to these alterations with what he now saw was frightening efficiency. It was as if the color changes warned of some malignancy in part of the Wall, and by touching it-expressing some tactile code-Felka was able to restructure the etchwork to block and neutralize the malignancy before it spread.

“I don’t understand,” Clavain said. “I thought we destroyed the Wall; completely killed its systems.”

“No,” Galiana said. “You only ever injured it. Stopped it from growing, and from managing its own repair-processes correctly…but you never truly killed it.”

Sandra Voi had guessed, Clavain realized. She had wondered how the Wall had survived this long.

Galiana told him the rest-how they had managed to establish control pathways to the Wall from the nest, fifteen years earlier-optical cables sunk deep below the worm zone. “We stabilized the Wall’s degradation with software running on dumb machines,” she said. “But when Felka was born we found that she managed the task just as efficiently as the computers; in some ways better than they ever did. In fact, she seemed to thrive on it. It was as if in the Wall she found…” Galiana trailed off. “I was going to say a friend.”

“Why don’t you?”

“Because the Wall’s just a machine. Which means if Felka recognized kinship…what would that make her?”

“Someone lonely, that’s all.” Clavain watched the girl’s motions. “She seems faster than before. Is that possible?”

“I told you things were worse than before. She’s having to work harder to hold the Wall together.”

“Warren must have attacked it.” Clavain said. “The possibility of knocking down the Wall always figured in our contingency plans for another war. I just never thought it would happen so soon.” Then he looked at Felka. Maybe it was imagination but she seemed to be working even faster than when he had entered the room; not just since his last visit. “How long do you think she can keep it together?”

“Not much longer,” Galiana said. “As a matter of fact I think she’s already failing.”

It was true. Now that he looked closely at the ghost Wall he saw that the upper edge was not the mathematically smooth ring it should have been; that there were scores of tiny ragged bites eating down from the top. Felka’s activities were increasingly directed to these opening cracks in the structure; instructing the crippled structure to divert energy and raw materials to these critical failure points. Clavain knew that the distant processes Felka directed were awesome. Within the Wall lay a lymphatic system whose peristaltic feed-pipes ranged in size from meters across to the submicroscopic; flowing with myriad tiny repair machines. Felka chose where to send those machines; her hand gestures establishing pathways between damage points and the factories sunk into the Wall’s ramparts which made the required types of machine. For more than a decade, Galiana said, Felka had kept the Wall from crumbling-but for most of that time her adversary had been only natural decay and accidental damage.

It was a different game now that the Wall had been attacked again. It was not one she could ever win.

Felka’s movements were swifter; less fluid. Her face remained impassive, but in the quickening way that her eyes darted from point to point it was possible to read the first hints of panic. No surprise, either: the deepest cracks in the structure now reached a quarter of the way to the surface, and they were too wide to be repaired. The Wall was unzipping along those flaws. Cubic kilometers of atmosphere would be howling out through the openings. The loss of pressure would be immeasurably slow at first, for near the top the trapped cylinder of atmosphere was only fractionally thicker than the rest of the Martian atmosphere. But only at first…

“We have to get deeper,” Clavain said. “Once the Wall goes, we won’t have a chance in hell if we’re anywhere near the surface. It’ll be like the worst tornado in history.”

“What will your brother do? Will he nuke us?”

“No; I don’t think so. He’ll want to get hold of any technologies you’ve hidden away. He’ll wait until the dust storms have died down, then he’ll raid the nest with a hundred times as many troops as you’ve seen so far. You won’t be able to resist, Galiana. If you’re lucky you may just survive long enough to be taken prisoner.”

“There won’t be any prisoners,” Galiana said.

“You’re planning to die fighting?”

“No. And mass suicide doesn’t figure in our plans either. Neither will be necessary. By the time your brother reaches here, there won’t be anyone left in the nest.”

Clavain thought of the worms encircling the area; how small were the chances of reaching any kind of safety if it involved getting past them. “Secret tunnels under the worm zone, is that it? I hope you’re serious.”

“I’m deadly serious,” Galiana said. “And yes, there is a secret tunnel. The other children have already gone through it now. But it doesn’t lead under the worm zone.”

“Where, then?”

“Somewhere a lot further away.”

When they passed through the medical center again it was empty, save for a few swan-necked robots patiently waiting for further casualties. They had left Felka behind tending the Wall, her hands a manic blur as she tried to slow the rate of collapse. Clavain had tried to make her come with them, but Galiana had told him he was wasting his time: that she would sooner die than be parted from the Wall.

“You don’t understand,” Galiana said. “You’re placing too much humanity behind her eyes. Keeping the Wall alive is the single most important fact of her universe-more important than love, pain, death-anything you or I would consider definitively human.”

“Then what happens to her when the Wall dies?”

“Her life ends,” Galiana said.

Reluctantly he had left without her, the taste of shame in his mouth. Rationally it made sense: without Felka’s help the Wall would collapse much sooner and there was a good chance all their lives would end; not just that of the haunted girl. How deep would they have to go before they were safe from the suction of the escaping atmosphere? Would any part of the nest be safe?

The regions through which they were descending now were as cold and gray as any Clavain had seen.

There were no entoptic generators buried in these walls to supply visual information to the implants Galiana had put in his head, and even her own aura of light was gone. They only met a few other Conjoiners, and they seemed to be moving in the same general direction; down to the nest’s basement levels. This was unknown territory to Clavain.

Where was Galiana taking him? “If you had an escape route all along, why did you wait so long before sending the children through it?”

“I told you, we couldn’t bring them to Transenlightenment too soon. The older they were, the better,”

Galiana said. “Now though…”

“There was no waiting any longer, was there?”

Eventually they reached a chamber with the same echoing acoustics as the topside hangar. The chamber was dark except for a few pools of light, but in the shadows Clavain made out discarded excavation equipment and freight pallets; cranes and de-activated robots. The air smelled of ozone. Something was still going on here.

“Is this the factory where you make the shuttles?” Clavain said.

“We manufactured parts of them here, yes,” Galiana said. “But that was a side-industry.”

“Of what?”

“The tunnel, of course.” Galiana made more lights come on. At the far end of the chamber-they were walking toward it-waited a series of cylindrical things with pointed ends; like huge bullets. They rested on rails, one after the other. The tip of the very first bullet was next to a dark hole in the wall. Clavain was about to say something when there was a sudden loud buzz and the first bullet slammed into the hole. The other bullets-there were three of them now-eased slowly forward and halted. Conjoiners were waiting to board them.

He remembered what Galiana had said about no one being left behind.

“What am I seeing here?”

“A way out of the nest,” Galiana said. “And a way off Mars, though I suppose you figured that part for yourself.”

“There is no way off Mars,” Clavain said. “The interdiction guarantees that. Haven’t you learned that with your shuttles?”

“The shuttles were only ever a diversionary tactic,” Galiana said. “They made your side think we were still striving to escape, whereas our true escape route was already fully operational.”

“A pretty desperate diversion.”

“Not really. I lied to you when I said we didn’t clone. We did-but only to produce brain-dead corpses.

The shuttles were full of corpses before we ever launched them.”

For the first time since leaving Deimos Clavain smiled, amused at the sheer obliquity of Galiana’s thinking.

“Of course, there was another function,” she said. “The shuttles provoked your side into a direct attack against the nest.”

“So this was deliberate all along?”

“Yes. We needed to draw your side’s attention; to concentrate your military presence in low-orbit, near the nest. Of course we were hoping the offensive would come later than it did…but we reckoned without Warren’s conspiracy.”

“Then you are planning something.”

“Yes.” The next bullet slammed into the wall, ozone crackling from its linear induction rails. Now only two remained. “We can talk later. There isn’t much time now.” She projected an image into his visual field: the Wall, now veined by titanic fractures down half its length. “It’s collapsing.”

“And Felka?”

“She’s still trying to save it.”

He looked at the Conjoiners boarding the leading bullet; tried to imagine where they were going. Was it to any kind of sanctuary he might recognize-or to something so beyond his experience that it might as well be death? Did he have the nerve to find out? Perhaps. He had nothing to lose now, after all; he could certainly not return home. But if he was going to follow Galiana’s exodus, it could not be with the sense of shame he now felt in abandoning Felka.

The answer, when it came, was simple. “I’m going back for her. If you can’t wait for me, don’t. But don’t try and stop me doing this.”

Galiana looked at him, shaking her head slowly. “She won’t thank you for saving her life, Clavain.”

“Maybe not now,” he said.

He had the feeling he was running back into a burning building. Given what Galiana had said about the girl’s deficiencies-that by any reasonable definition she was hardly more than an automaton-what he was doing was very likely pointless, if not suicidal. But if he turned his back on her, he would become something even less than human himself. He had misread Galiana badly when she said the girl was precious to them. He had assumed some bond of affection…whereas what Galiana meant was that the girl was precious in the sense of a vital component. Now-with the nest being abandoned-the component had no further use. Did that make Galiana as cold as a machine herself-or was she just being unfailingly realistic? He found the nursery after only one or two false turns, and then Felka’s room.

The implants Galiana had given him were again throwing phantom images into the air. Felka sat within the crumbling circle of the Wall. Great fissures now reached to the surface of Mars. Shards of the Wall, as big as icebergs, had fractured away and now lay like vast sheets of broken glass across the regolith.

She was losing, and now she knew it. This was not just some more difficult phase of the game. This was something she could never win, and her realization was now plainly evident in her face. She was still moving her arms frantically, but her face was red now, locked into a petulant scowl of anger and fear.

For the first time, she seemed to notice him.

Something had broken through her shell, Clavain thought. For the first time in years, something was happening that was beyond her control; something that threatened to destroy the neat, geometric universe she had made for herself. She might not have distinguished his face from all the other people who came to see her, but she surely recognized something…that now the adult world was bigger than she was, and it was only from the adult world that any kind of salvation could come.

Then she did something that shocked him beyond words. She looked deep into his eyes and reached out a hand.

But there was nothing he could do to help her.

Later-it seemed hours, but in fact could only have been tens of minutes-Cla-vain found that he was able to breathe normally again. They had escaped Mars now; Galiana, Felka and himself, riding the last bullet.

And they were still alive.

The bullet’s vacuum-filled tunnel cut deep into Mars; a shallow arc bending under the crust before rising again, two thousand kilometers away, well beyond the Wall, where the atmosphere was as thin as ever.

For the Conjoiners, boring the tunnel had not been especially difficult. Such engineering would have been impossible on a planet that had plate tectonics, but beneath its lithosphere Mars was geologically quiet.

They had not even had to worry about tailings. What they excavated, they compressed and fused and used to line the tunnel, maintaining rigidity against awesome pressure with some trick of piezo-electricity.

In the tunnel, the bullet accelerated continuously at three gees for six minutes. Their seats had tilted back and wrapped around them, applying pressure to the legs to maintain blood flow to the head. Even so, it was hard to think, let alone move, but Clavain knew that it was no worse than what the earliest space explorers had endured climbing away from Earth. And he had undergone similar tortures during the war, in combat insertions.

They were moving at ten kilometers a second when they reached the surface again, exiting via a camouflaged trapdoor. For a moment the atmosphere snatched at them…but almost as soon as Clavain had registered the deceleration, it was over. The surface of Mars was dropping below them very quickly indeed.

In half a minute, they were in true space.

“The Interdiction’s sensor web can’t track us,” Galiana said. “You placed your best spysats directly over the nest. That was a mistake, Clavain-even though we did our best to reinforce your thinking with the shuttle launches. But now we’re well outside your sensor footprint.”

Clavain nodded. “But that won’t help us once we’re far from the surface. Then, we’ll just look like another ship trying to reach deep space. The web may be late locking onto us, but it’ll still get us in the end.”

“It would,” Galiana said. “If deep space was where we were going.”

Felka stirred next to him. She had withdrawn into some kind of catatonia. Separation from the Wall had undermined her entire existence; now she was free-falling through an abyss of meaninglessness. Perhaps, Clavain, thought, she would fall forever. If that was the case, he had only brought forward her fate. Was that much of a cruelty? Perhaps he was deluding himself, but with time, was it out of the question that Galiana’s machines could undo the harm they had inflicted ten years earlier? Surely they could try. It depended, of course, on where exactly they were headed. One of the system’s other Conjoiner nests had been Clavain’s initial guess-even though it seemed unlikely that they would ever survive the crossing. At ten klicks per second it would take years…

“Where are you taking us?” he asked.

Galiana issued some neural command which made the bullet seem to become transparent.

“There,” she said.

Something lay distantly ahead. Galiana made the forward view zoom in, until the object was much clearer.

Dark-misshapen. Like Deimos without fortifications.

“Phobos,” Clavain said, wonderingly. “We’re going to Phobos.”

“Yes,” Galiana said.

“But the worms-”

“Don’t exist anymore.” She spoke with the same tutorly patience with which Remontoire had addressed him on the same subject not long before. “Your attempt to oust the worms failed. You assumed our subsequent attempt failed…but that was only what we wanted you to think.”

For a moment he was lost for words. “You’ve had people in Phobos all along?”

“Ever since the cease-fire, yes. They’ve been quite busy, too.”

Phobos altered. Layers of it were peeled away, revealing the glittering device which lay hidden in its heart, poised and ready for flight. Clavain had never seen anything like it, but the nature of the thing was instantly obvious. He was looking at something wonderful; something which had never existed before in the whole of human experience.

He was looking at a starship.

“We’ll be leaving soon,” Galiana said. “They’ll try and stop us, of course. But now that their forces are concentrated near the surface, they won’t succeed. We’ll leave Phobos and Mars behind, and send messages to the other nests. If they can break out and meet us, we’ll take them as well. We’ll leave this whole system behind.”

“Where are you going?”

“Shouldn’t that be where are we going? You’re coming with us, after all.” She paused. “There are a number of candidate systems. Our choice will depend on the trajectory the Coalition forces upon us.”

“What about the Demarchists?”

“They won’t stop us.” It was said with total assurance-implying, what? That the Demarchy knew of this ship? Perhaps. It had long been rumored that the Demarchists and the Conjoiners were closer than they admitted.

Clavain thought of something. “What about the worms’ altering the orbit?”

“That was our doing,” Galiana said. “We couldn’t help it. Every time we send up one of these canisters, we nudge Phobos into a different orbit. Even after we sent up a thousand canisters, the effect was tiny-we changed Phobos’s velocity by less than one tenth of a millimeter per second-but there was no way to hide it.” Then she paused and looked at Clavain with something like apprehension. “We’ll be arriving in two hundred seconds. Do you want to live?”

“I’m sorry?”

“Think about it. The tube in Mars was two thousand kilometers long, which allowed us to spread the acceleration over six minutes. Even then it was three gees. But there simply isn’t room for anything like that in Phobos. We’ll be slowing down much more abruptly.”

Clavain felt the hairs on the back of his neck prickle. “How much more abruptly?”

“Complete deceleration in one fifth of a second.” She let that sink home. “That’s around five thousand gees.”

“I can’t survive that.”

“No; you can’t. Not now, anyway. But there are machines in your head now. If you allow it, there’s time for them to establish a structural web across your brain. We’ll flood the cabin with foam. We’ll all die temporarily, but there won’t be anything they can’t fix in Phobos.”

“It won’t just be a structural web, will it? I’ll be like you, then. There won’t be any difference between us.”

“You’ll become Conjoined, yes.” Galiana offered the faintest of smiles. “The procedure is reversible. It’s just that no one’s ever wanted to go back.”

“And you still tell me none of this was planned?”

“No; but I don’t expect you to believe me. For what it’s worth, though…you’re a good man, Nevil. The Transenlightenment could use you. Maybe at the back of my mind…at the back of our mind…”

“You always hoped it might come to this?”

Galiana smiled.

He looked at Phobos. Even without Galiana’s magnification, it was clearly bigger. They would be arriving very shortly. He would have liked longer to think about it, but the one thing not on his side now was time.

Then he looked at Felka, and wondered which of them was about to embark on the stranger journey.

Felka’s search for meaning in a universe without her beloved Wall, or his passage into Transenlightenment? Neither would necessarily be easy. But together, perhaps, they might even find a way to help each other. That was all he could hope for now.

Clavain nodded assent, ready for the loom of machines to embrace his mind.

He was ready to defect.