“Basically,” Aurelia said, “the virus has hitched a ride on our collective immune system.”

She tore a sheet of paper from her notebook and began sketching bold lines and circles to illustrate her point. One circle was labeled susceptible individuals,another immune individuals,another asymptomatic carriers.Under her hands, the lines and circles quickly mustered into the standard flowchart that illustrated the way diseases and immunities spread through human and Syndicate populations.

“The collective immune system—of which the Motai version is the most aggressive—operates along the same lines as horizontal DNA transfer between virus variants within an infected host. It’s an intelligent adaptation to life in space. The human immune system evolved on Earth, where you had large, genetically diverse, low-density populations living in the open air or in primitive, well-ventilated dwellings. Disease spread slowly, and even major epidemics were no real threat in evolutionary terms since the overall population was always large enough to buffer against excess mortality. In that environment there’s actually a major evolutionary advantage to letting diseases spread widely enough to elicit a diversity of immune responses and avoid immunodominance problems.

“But in the Syndicates, we have tiny populations with minimal genetic diversity living on space stations where pathogens spread like wildfire. A severe epidemic can literally wipe out an entire geneline; it happened several times before we developed the current immunological splices. So our immune systems are designed with one goal in mind: killing new pathogens before they have a chance to get a foothold…even if that means giving up on the Earth-evolved mechanisms that ensure a diverse and balanced immune response in the longer, evolutionary timescale. We’ve used two tools to do it: horizontal DNA transfer that confers ‘inherited’ immunity without the time lag of waiting for genes to be passed on to the next generation; and a hard-hitting, fast-maturing immune response profile.

“Both splices are double-edged swords. And Novalis has turned them both against us. I can’t tell you if the virus is designed to infect us or not,” she finished darkly, “but I can tell you that the fit couldn’t be more perfect.”

As if by some tacit agreement, all eyes turned to Arkasha.

“Bottom line?” Arkasha said, speaking directly to By-the-Book Ahmed. “It’s not a weapon. It’s a terraforming tool. The most brilliant terraforming tool anyone could imagine. A viral search engine that expands its population—and therefore its parallel processing capacity—by jumping into every new species it encounters. And then expands it some more by pushing infected individuals into evolutionary overdrive. It’s a diversity machine. And it’s created a global red queen regime where every organism on this planet is running and running just to make the world stand still.”

“If it’s a terraforming tool,” By-the-Book Ahmed inquired icily, “then who put it here?”

“The original colonists. The UN. Little green men. I don’t care. All I know is it works. It works so well that there’s a real chance that other ship you’re so worried about wasn’t Peacekeepers but colonists.”

“Colonists with cutting-edge UN military technology?” Ahmed asked. Obviously the question was rhetorical.

“Maybe we need to go back to Aurelia’s first point,” Arkasha said. To Arkady’s surprise he was holding his temper in the face of Ahmed’s attacks. Perhaps it was a sign of the importance he placed on the outcome of this consult. “The immunological splices have always been the weak link in Syndicate physiology. It was the right trade-off to make, but we knew it might come back to haunt us someday. This thing hit us so hard because our immune systems happen to be an ideal vector for it, not necessarily because it was intentionally targeted at us.”

“If you step on one of Arkady’s ants,” By-the-Book Ahmed asked trenchantly, “does it matter to the ant whether you killed it on purpose or by accident?”

“Still,” Arkasha insisted, “we don’t know it’s the Peacekeepers. That’s a big jump.”

“Then explain why we didn’t see them come in-system?” By-the-Book Ahmed asked. “They have to have kept the planet between us and them for every kilometer of their in-system flight or our navcomp would have picked them up. Do I need to draw you a map? Do you have any ideahow minute an area of space the solutions for that trajectory occupy? Talk about putting a camel through the eye of a needle!”

“I still don’t see why we can’t get more information before we—”

“What do you want us to do, fly around to the other hemisphere and politely ask them if they’re here to kill us? If they are, then I guarantee you the only reason we’re still alive is that they haven’t figured out where we are yet. We’re running on UN commercial technology that was already obsolete when we left Gilead three years ago. Fact of life. If we go out looking for them, they’ll find us a hell of a long time before we find them!”

They argued the question back and forth for a while, getting nowhere. Arkady had seen this dynamic in other consults: people talking around a problem not because they were still making up their minds, but because they needed to put mileage between themselves and their doubts. And in this consult Arkady sensed an emotional undertow that he suspected would be ominously familiar to anyone who’d lived through the bloody and bewildering weeks that followed the UN invasion.

His crewmates were frightened. They were terrified. And in their terror they turned to the tacticals.

The only real and effective support for Arkasha’s position came from a quarter that was as unexpected as it was welcome: Laid-back Ahmed.

“I think we’re losing sight of the real priorities here,” he said finally with the calm confidence that had made him the more or less undisputed mission leader ever since they woke up. Arkady could see team members glancing covertly at each other, taking stock, reexamining their previous assumptions in light of Ahmed’s calm rationality. “It’s not our personal safety that matters, it’s our long-term ability to settle this planet. Thawing out the tacticals and retreating into orbit may make us feel safer, but it won’t do a thing to solve the real problems facing us. The only way to do that is to stick to our guns and let the scientists keep working.”

“But what does that matter if their work is lost because we get—”

“It doesn’t need to be lost,” Arkasha jumped in. “We can just start shooting message drogues to the out-system relay daily instead of weekly. That way nothing’s being lost. Our data and questions and theories will all get to Gilead.”

“But not soon enough to save us if—”

“Since when did this become about saving us? If we go home without having gotten our job done, then we might as well have let whoever’s out there kill us.” Arkasha looked around the table incredulously. “What’s happening to you people? Where’s your altruism? You’re acting like humans,for God’s sake!”

And then Bella said the awful words that changed everything:

“You weren’t so worried about acting human when you got my crèchemate pregnant.”

A chill settled over the room. Arkasha froze. The others shrank away from him, looking in every other possible direction.

In retrospect it seemed incomprehensible, but until Bella made her accusation everyone had been so overwhelmed by the fact of Bella’s beingpregnant that it had never occurred to them to wonder who’d helped her get that way. And of course they would all suspect Arkasha long before their thoughts turned to Ahmed. Arkasha the contrarian. Arkasha the intellectual. It was only a short step from there to Arkasha the deviant.

Arkady sought Laid-back Ahmed’s eyes across the table, but the big Aziz A was looking at Arkasha. The two of them stared at each other for what would have been a breath’s length if anyone in the room had been breathing. Ahmed looked stunned. Arkasha looked as if he were wavering on the brink of a choice he didn’t want to have to make.