Jutta squeezes his knee. They glance at each other; she smiles. He puts his hand over hers.

His eyes drift back to the floor. Very gently, he begins nodding again.

"Jakob wasn't close to the research teams," Jutta explains. "Scientists aren't all that good with people, as you know. It would be a disaster to let some of those people act as spokespersons, but they still resented the way Jakob presented their findings sometimes."

Rowan smiles patiently. "The thing is, Jakob, I've been thinking. About ßehemoth, and how old it is—"

"Oldest goddamn life on the planet," Jakob says. "The rest of us, we just dropped in later. Martian meteor or something. Bloody ßehemoth, it's the only thing that actually started here."

"But that's the thing, isn't it? ßehemoth doesn't just predate other life, it predates photosynthesis. It predates oxygen. It's over four billion years old. And all the other really ancient bugs we've found, the Archaebacteria and the Nanoliths and so forth, they're still anaerobes to this day. You only find them in reducing environments. And yet here's ßehemoth, even older, and oxygen doesn't bother it at all."

Jacob Holtzbrink stops rocking.

"Smart little bug," he says. "Keeps up with the times. Has those, what do you call them, like Pseudomonas has—"

"Blachford genes. Change their own mutation rate under stress."

"Right. Right. Blachford genes." Jakob brings one hand up, runs it over a sparsely-haired and liver-spotted scalp. "It adapted. Adapted to oxygen, and adapted to living inside fishes, and now it's adapting to every other goddamn nook and cranny on the goddamn planet."

"Only it never adapted to low temperature and high salinity in combination," Rowan observes. "It never adapted to the single biggest habitat on Earth. The deep sea stumped it for billions of years. The deep sea would still be stumping it if the Channer outbreak hadn't happened."

"What are you saying?" Jutta wonders, a sudden slight sharpness in her voice. Her husband says nothing.

Rowan takes a breath. "All our models are based on the assumption that ßehemoth has been in its present form for hundreds of millions of years. The advent of oxygen, hypotonic host bodies—all that happened in the deep, deep Precambrian. And we know that not much has changed since then, Blachford genes or no Blachford genes—because if it had, ßehemoth would have ruled the world long before now. We know it can't disperse through the abyss because it hasn't dispersed through the abyss, in all the millions of years it's had to try. And when someone suggests that maybe it hitched a ride in the ichthyoplankton, we dismiss them out of hand not because anybody's actually checked—who had the time, the way things were going?—but because if it could disperse that way, it would have dispersed that way. Millions of years ago."

Jakob Holtzbrink clears his throat.