The thought of Devi made the cold terror curl through my stomach again, winding itself around my spine. These people were dangerous. Even restrained, they were dangerous, and all of them, even the frail Ms. Lawrence, were upset. I didn’t know why. That wasn’t going to matter if they managed to break loose.

Dr. Snyder met us at Ms. Lawrence’s cot, a UV wand in her hand. “The lights will be dimmed on your order, sir,” she said, offering the wand to my father.

“Thank you,” he said. He took the wand and passed it to me. “Sally?”

“Lights, please,” I half-whispered.

“Lights!” my father repeated, much more loudly. The technicians and doctors who had been moving around the room stopped where they were, except for the few who moved toward us, apparently wanting to see what I was going to do. Someone hit a switch, and the room’s overhead and ambient lighting decreased, slowly shifting us from artificial day into artificial twilight.

“Can someone get her arm, please?” I asked, turning on the UV wand. It hummed silently in my hand, the sound translating itself into a vibration that traveled through my fingers to my wrist. I swept the wand across the front of my shirt to be sure that it was working, and watched the fabric light up like something out of a bad special effect.

“How do you want it?” asked my father, pulling on a pair of plastic gloves as he stepped past me to the moaning, barely squirming Ms. Lawrence.

“Turn it so that the top of her hand is pressed against the cot,” I said.

He did as I had asked, and everyone was silent as I passed the beam above Ms. Lawrence’s arm. As I had expected, the roots of the parasitic infection responsible for her illness showed up immediately, bright white against the dull purple of her skin. They were thinner and less robust than the roots I’d seen on Nathan’s patient, probably because Ms. Lawrence was older, and had fewer resources for the parasite to draw on.

“What in the world…?” breathed my father.

The roots twitched, seeming to respond to the light that was shining over them. They didn’t move much, but they were definitely moving toward the light.

One of the thicker roots jerked toward Joyce. She made a small squeaking noise, taking a half step backward.

“The sleepwalking sickness isn’t. I mean, it’s actually a parasite, sort of,” I said. “It’s the SymboGen implant. It’s… doing things.” I didn’t want to tell them exactly what it was doing, in part because I didn’t understand it without Dr. Cale or Nathan there to explain, and more because I didn’t trust them anymore. Yes, this was my family, and yes, they loved me, but their focus was on the public health. It had to be.

If they were willing to scare me because they thought I might know something, what would they be willing to do to Nathan and Dr. Cale? What would they do to Tansy, or to Adam? Tansy was probably a sociopath—if a tapeworm in a meat car can be a sociopath—but she didn’t deserve to become a lab animal.

And none of these people deserved to be sick. I didn’t know what to do. I only had six years of living to draw on, and it wasn’t enough. I didn’t know what to do.

From the looks on the faces around me, neither did anyone else. Joyce was the first to recover, asking, “How sure about this are you, Sal? I mean… D. symbogenesis is an intestinal parasite. It can’t spread through muscular tissue. That just doesn’t make any sense.”

“Nature doesn’t have to make sense. Nature just does.” I moved the UV light along Ms. Lawrence’s arm, causing more of the roots to twitch and writhe away. “What kind of virus could cause this sort of a reaction? If there is one, I don’t know what it is. But you’re the ones with the medical training. Maybe I’m wrong.” I looked up, challenging them to offer another explanation.

None of them did. Instead, my father let go of Ms. Lawrence, held out his arm, and said, “Check me.”

“Dad—” Joyce began.

“Just because I’m not symptomatic, that doesn’t mean I’m not worth examining,” he said, cutting her off. “Sal, if you please?”

It had the feeling of a test. Still, I stepped toward him, holding up the UV light. “Just give me your arm.”

Next to us, Dr. Snyder was frowning at Ms. Lawrence’s unmarked skin. The roots were invisible now that the UV light was no longer shining on her. “It seems so strange that there would be no exterior signs…” she said, reaching out to touch the old woman.

What happened after that happened very quickly, and I didn’t fully understand it until later—until I’d had the time to really think, instead of just reacting.

Ms. Lawrence, who had been frail when she was committed to the care of USAMRIID, had continued to lose weight throughout her treatment; her overlarge hospital gown made that clear. They’d probably stopped tightening her restraints after a certain point, both because she seemed too weak to pose a problem, and because they didn’t want to hurt her. That’s why she was able to rip her left arm free of the straps that were meant to be holding it to the table. In a single convulsive motion, she had hold of Dr. Snyder’s throat, clamping down with a strength that I wouldn’t have thought her fingers still possessed.

Dr. Snyder flailed, knocking the UV light out of my hands. It went skidding across the floor as I stumbled back, stopping when my back hit another cot. The occupant was snarling and snapping at the air, trying to struggle free of his bonds—but either he was a more recent arrival or they had been more mindful of security where he was concerned, because his efforts to break loose were unsuccessful.