Xiomara shook her head, sending shivers of motion through her frost-edged dreadlocks. “We have to stop thinking of it as a virus. We saw it moving through Ariana. That’s not a virus.” Her tears were drying up, her voice growing stronger. “The doctors and SPEC got it wrong. It’s big enough to be seen through the skin, and it grows quickly from the point of infection, and it’s at least partly mechanical. It’s some kind of bioengineered parasite.”

“If it’s even bio-anything,” Baqir said. “It could be entirely mechanical. If there was some sort of transceiver or radio—”

“It could have recorded my parents’ words,” I said.

Xiomara nodded thoughtfully. “There are neuromedical devices that are triggered by changes in body temperature and chemistry. Something like that—when it got into Ariana, if it sensed the right conditions, it would wake from a dormant state and begin functioning again. It might have detected a signal from the other one, the one in . . .” She winced as she looked at me. “The one in your father. We warmed up the room, gave it favorable conditions again. Temperature might be the trigger for activity. The device in Ariana knew it was waking. That’s why she followed us there.”

“Fuck,” Baqir said. “They were never hallucinating. None of them.”

“It would have to have very high-level nerve control. Brain systems and autonomic functions. Voluntary functions, too, if it can take over and make the hosts move and speak. Is that even possible? Does technology like that exist? You must know something about the research into communication between brain and machine,” Xiomara said to Baqir.

“A little,” he conceded, which I knew was a massive understatement. He was flexing the fingers of his metal hand, frowning in thought. After a moment he said, “It’s not impossible. But most neural engineering is on interfaces that work the other way around—getting signals from the brain to control external devices. The research on signaling the other way . . . nothing I’ve ever heard of can even get close to using an engineered device to control higher brain functions. Things like making muscles twitch, controlling spasms, anything that’s a straightforward electrical effect, that’s easy. But speech and decision-making and mimicry . . . I don’t know. I’ve never heard of it.”

“And after death?” I said.

Baqir touched my arm. “I don’t know. It might be—what we saw in Ariana was big enough to see. It might grow large enough for crude motor manipulation, even without any neural input. Or life signs.”

“We have to assume it’s possible,” Xiomara said. She lifted her hand to her neck, and I tensed—looked for any sign of motion, for any squirm of discomfort—but she was only adjusting the suit’s collar. She saw me staring and moved her hand away. “If it’s a biomechanical parasite, we can help Ari. Somebody can take it out.”