"Targeted delivery. Drugs, genes, replacement organelles. Its cell wall, you've never seen anything like it. Nothing has. No immune response to worry about, slips past counterintrusion enzymes like they were blind and deaf. Target cell takes it right in, lyses the wall, COD. Like a biodegradable buckyball."

"What else?"

"The ultimate pep pill. Under the right conditions the thing pumps out ATP so fast you could roll a car over single-handed. Makes mitochondria look like yesterday's sockeye. Soldier with ßehemoth in his cells might even give an exoskel a run for the money, if you feed him enough."

"And if ßehemoth were tweaked properly," Rowan amends.

"Aye," whispers the old man. "There's the rub."

Rowan chooses her words very carefully. "Might there have been any…less precise applications? MAD machines? Industrial terrorism?"

"You mean, like what it does now? No. W—someone would have to be blind and stupid and insane all at once to design something like that."

"But you'd have to increase the reproductive rate quite a bit, wouldn't you? To make it economically viable."

He nods, his eyes still on far-focus. "Those deep-rock dwellers, they live so slow you're lucky if they divide once a decade."

"And that would mean they'd have to eat a lot more, wouldn't it? To support the increased growth rate."

"Of course. Child knows that much. But that's not why you'd do it, nobody would do that because they wanted something that could—it would just be a, an unavoidable—"

"A side effect," Jutta suggests.

"A side effect," he repeats. His voice hasn't changed. It still rises, calm and distant, from the center of the earth. But there are tears on Jakob Holtzbrinck's face.

"So nobody did it deliberately. They were aiming for something else, and things just—went wrong. Is that what you're saying?"

"You mean, hypothetically?" The corners of his mouth lift and crinkle in some barely-discernible attempt at a smile. A tear runs down one of those fleshy creases and drops off his chin.

"Yes, Jakob. Hypothetically."

The head bobs up and down.

"Is there anything we can do? Anything we haven't tried?"

Jakob shakes his head. "I'm just a corpse. I don't know."

She stands. The old man stares down into his own thoughts. His wife stares up at Rowan.

"What he's told you," she says. "Don't take it the wrong way."

"What do you mean?"

"He didn't do this, any more than you did. He's no worse than the rest of you."

Rowan inclines her head. "I know, Fran."

She excuses herself. The last thing she sees, as the hatch seals them off, is Fran Holtzbrink sliding a lucid dreamer over her husband's bowed head.