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.”
