"Sarasti doesn't guess," Bates said. "The man's in charge for a reason. Doesn't make much sense to question his orders, given we're all about a hundred IQ points short of understanding the answer anyway."

"And yet he's also got that whole predatory side nobody talks about," I remarked. "It must be difficult for him, all that intellect coexisting with so much instinctive aggression. Making sure the right part wins."

She wondered in that instant whether Sarasti might be listening in. She decided in the next that it didn't matter: why should he care what the cattle thought, as long as they did what they were told?

All she said was, "I thought you jargonauts weren't supposed to have opinions."

"That wasn't mine."

Bates paused. Returned to her inspection.

"You do know what I do," I said.

"Uh huh." The first of the current pair passed muster and hummed off up the spine. She turned to the second. "You simplify things. So the folks back home can understand what the specialists are up to."

"That's part of it."

"I don't need a translator, Siri. I'm just a consultant, assuming things go well. A bodyguard if they don't."

"You're an officer and a military expert. I'd say that makes you more than qualified when it comes to assessing Rorschach's threat potential."

"I'm muscle. Shouldn't you be simplifying Jukka or Isaac?"

"That's exactly what I'm doing."

She looked at me.

"You interact," I said. "Every component of the system affects every other. Processing Sarasti without factoring you in would be like trying to calculate acceleration while ignoring mass."

She turned back to her brood. Another robot passed muster.

She didn't hate me. What she hated was what my presence implied.

They don't trust us to speak for ourselves, she wouldn't say. No matter how qualified we are, no matter how far ahead of the pack. Maybe even becauseof that. We're contaminated. We're subjective. So they send Siri Keeton to tell them what we reallymean.

"I get it," I said after a moment.

"Do you."

"It's not about trust, Major. It's about location. Nobody gets a good view of a system from the inside, no matter who they are. The view's distorted."

"And yours isn't."

"I'm outside the system."

"You're interacting with me now."

"As an observer only. Perfection's unattainable but it isn't unapproachable, you know? I don't play a role in decision-making or research, I don't interfere in any aspect of the mission that I'm assigned to study. But of course I ask questions. The more information I have, the better my analysis."

"I thought you didn't have to ask. I thought you guys could just, read the signs or something."

"Every bit helps. It all goes into the mix."

"You doing it now? Synthesizing?"

I nodded.

"And you do this without any specialized knowledge at all."

"I'm as much of a specialist as you. I specialize in processing informational topologies."

"Without understanding their content."

"Understanding the shapes is enough."

Bates seemed to find some small imperfection in the battlebot under scrutiny, scratched at its shell with a fingernail. "Software couldn't do that without your help?"

"Software can do a lot of things. We've chosen to do some for ourselves." I nodded at the grunt. "Your visual inspections, for example."

She smiled faintly, conceding the point.

"So I'd encourage you to speak freely. You know I'm sworn to confidentiality."

"Thanks," she said, meaning On this ship, there's no such thing.

Theseus chimed. Sarasti spoke in its wake: "Orbital insertion in fifteen minutes. Everyone to the drum in five."

"Well," Bates said, sending one last grunt on its way. "Here we go." She pushed off and sailed up the spine.

The newborn killing machines clicked at me. They smelled like new cars.

"By the way," Bates called over her shoulder, "you missed the obvious one."

"Sorry?"

She spun a hundred-eighty degrees at the end of the passageway, landed like an acrobat beside the drum hatch. "The reason. Why something would attack us even if we didn't have anything it wanted."

I read it off her: "If it wasn't attacking at all. If it was defending itself."

"You asked about Sarasti. Smart man. Strong Leader. Maybe could spend a little more time with the troops."

Vampire doesn't respect his command. Doesn't listen to advice. Hides away half the time.

I remembered transient killer whales. "Maybe he's being considerate." He knows he makes us nervous.

"I'm sure that's it," Bates said.

Vampire doesn't trust himself.

It wasn't just Sarasti. They all hid from us, even when they had the upper hand. They always stayed just the other side of myth.

It started pretty much the same way it did for anything else; vampires were far from the first to learn the virtues of energy conservation. Shrews and hummingbirds, saddled with tiny bodies and overclocked metabolic engines, would have starved to death overnight if not for the torpor that overtook them at sundown. Comatose elephant seals lurked breathless at the bottom of the sea, rousing only for passing prey or redline lactate levels. Bears and chipmunks cut costs by sleeping away the impoverished winter months, and lungfish—Devonian black belts in the art of estivation—could curl up and die for years, waiting for the rains.

With vampires it was a little different. It wasn't shortness of breath, or metabolic overdrive, or some blanket of snow that locked the pantry every winter. The problem wasn't so much a lack of prey as a lack of difference from it; vampires were such a recent split from the ancestral baseline that the reproductive rates hadn't diverged. This was no woodland-variety lynx-hare dynamic, where prey outnumbered predators a hundred to one. Vampires fed on things that bred barely faster than they did. They would have wiped out their own food supply in no time if they hadn't learned how to ease off on the throttle.

By the time they went extinct they'd learned to shut down for decades.

It made two kinds of sense. It not only slashed their metabolic needs while prey bred itself back to harvestable levels, it gave us time to forget that we were prey. We were so smart by the Pleistocene, smart enough for easy skepticism; if you haven't seen any night-stalking demons in all your years on the savannah, why should you believe some senile campfire ramblings passed down by your mother's mother?

It was murder on our ancestors, even if those same enemy genes—co-opted now—served us so well when we left the sun a half-million years later. But it was almost—heartening, I guess—to think that maybe Sarasti felt the tug of other genes, some aversion to prolonged visibility shaped by generations of natural selection. Maybe he spent every moment in our company fighting voices that urged him to hide, hide, let them forget. Maybe he retreated when they got too loud, maybe we made him as uneasy as he made us.

We could always hope.

Our final orbit combined discretion and valor in equal measure.

Rorschach described a perfect equatorial circle 87,900 km from Big Ben's center of gravity. Sarasti was unwilling to let it out of sight, and you didn't have to be a vampire to mistrust relay sats when swinging through a radiation-soaked blizzard of rock and machinery. The obvious alternative was to match orbits.

At the same time, all the debate over whether or not Rorschach had meant—or even understood—the threats it had made was a bit beside the point. Counterintrusion measures were a distinct possibility either way, and ongoing proximity only increased the risk. So Sarasti had derived some optimum compromise, a mildly eccentric orbit that nearly brushed the artefact at perigee but kept a discreet distance the rest of the time. It was a longer trajectory than Rorschach's, and higher—wehad to burn on the descending arc to keep in synch—but the end result was continuously line-of-sight, and only brought us within striking distance for three hours either side of bottoming out.