“They could have killed me,” I concluded. “But my body—Sally’s body, I mean, not the actual me—that would have been fine, right?” It was a surprisingly easy sentence to make myself utter. I was adapting. That, or I was still in shock. I hoped for the former, but I’d take either one if it kept me calm and capable of being an active part of my own future.

“Not necessarily. The brain controls the body to a very large degree, and your distress sent the body into anaphylactic shock when you were given antiparasitics. If they had been continued and mixed with enough epinephrine, yes, they could have killed you without killing your human half, but they would have damaged it severely.” Nathan looked almost ashamed of what he was saying. “On one of the newer generation of worms… there’s no guarantee the antiparasitics would work even that well. They’re too human. Doctors trying for treatment would have to move on to chemicals that can be dangerous to the human body, as well as to the invading parasites.”

“So everybody dies, or everybody lives,” I concluded. “Why would that seem like a good idea? Aren’t the antiparasitics supposed to, um, clear out the old worms so SymboGen can keep selling new ones to people?” The idea was suddenly repellent to me. Every time I’d discussed antiparasitics in the past—even demanded them, only a few hours before—it had been with the idea that they would improve the quality of a person’s life. As I was forced to reconsider what made a person, they suddenly looked like murder.

You’re adjusting to this too fast, murmured my thoughts.

But I wasn’t adjusting too fast: not really. I had known the truth for a while, allowing it to integrate itself with my deeper thinking, like it was a second tapeworm writhing and knotting its way through the first. I had invaded Sally Mitchell’s mind, and the truth of my origins had invaded mine. Fair was only fair.

“It doesn’t seem like a good idea,” said Dr. Cale. “If Steven did this, it’s because he was trying to orchestrate the current crisis. I just… I can’t…” Her face fell, allowing honest dismay to leak briefly through her so carefully constructed mask. “It’s bad for stock prices,” she said finally. “It’s going to destroy SymboGen. There’s no way he can recover from this. As soon as people realize that the implants are responsible, he’ll be finished, he’ll be lucky to walk away a free man—and even then, he’ll need to keep his eyes open for the rest of his life, or the family of one of the sleepwalkers will bring that life to a short and brutal end. It doesn’t make sense for Steven to have done this.”

I frowned. “Is surgery an option? Couldn’t they, you know…” I made a snipping motion with one hand, like it was a pair of scissors. “That’s how you got Adam out of you, right? You had your assistants cut you open.”

“We don’t have the facilities or the personnel for that sort of mass surgical intervention,” said Dr. Cale. “That also assumes the worms have not yet started to migrate. You’re so integrated with Sally Mitchell’s brain tissue at this point that we couldn’t remove you even if we wanted to. There’s a point past which there is no going back.”

“That means that all the sleepwalkers are past saving, surgically or otherwise,” added Nathan. “That ship has sailed.”

“Oh,” I said quietly. “So, um. How much time would it take for someone to modify the design on the implants? I know I’m… I mean my implant was… I mean I’m one of the older generations. I probably don’t have that much human DNA in me.”

“Given the generational cycle of D. symbogenesis—it’s compacted down to a matter of months when you’re working in a lab environment, outside of a human host—you could increase the human DNA to this level in two years, give or take a few quality control tests. Maybe a little longer, if you wanted to be absolutely sure of stability. Maybe a little less time, if you weren’t worried about side effects,” said Dr. Cale.

“Side effects like growing through the muscle tissue of your host and eventually trying to take them over?” I ventured. “I mean, apparently I did that too, but not until after Sally had her accident, when it was all a matter of survival. If I hadn’t taken over, we would both have died.”

“Yes, those would be considered side effects,” said Dr. Cale.

“So, um, how long ago did Sherman go all AWOL on you?” I frowned a little. “He’s been at SymboGen for as long as I can remember, and he had friends in the science department—Dr. Sanjiv and Dr. McGillis at the very least. Um, they used to do my MRIs, so I know they knew what I was, and Dr. Sanjiv was also I think in the genetics department? And Dr. McGillis was all about internal medicine, and anyway, I think he could probably have done it.”

“Sherman?” asked Nathan.

“You remember how I had those two handlers at SymboGen? The really pretty, really chilly lady and the tall dude who always had a tan even though he mostly worked underground?”

Nathan nodded. “Yes. He… ah, well, he tried to convince me to go out to dinner with him once.” He rubbed the back of his neck with one hand. “This was after I had told him I was there to pick you up, mind. He seemed to think that my having dinner with him would make me a better boyfriend for you. Fortunately, you showed up about that time, and he didn’t have the chance to press the issue.”