When I came around the corner, I didn’t understand what I was looking at—not at first. Adam had pulled the curtain away from the tiny exam room set up for Anna, who was still lying naked and unmoving on the bed. Dr. Cale and Nathan were a short distance away, Nathan with his hands resting on the handles of Dr. Cale’s wheelchair, Dr. Cale with one hand clasped over her mouth in a classic expression of horror. Her eyes were wide and brimming with unshed tears, like she had just realized something so terrible that she was no longer capable of forming words. Adam was standing with his hand still on the curtain of Anna’s “room,” staring at her.

I trotted up behind him, only wheezing a little, and asked, “Adam, why did you run away from me like that?”

“She’s here,” he said, sounding horrified and puzzled at the same time. He turned to me, that same conflict reflected in his face. “Can’t you feel her? She’s here, with us, but she’s not here at all. Sal, what did he do to her? What did he do to our sister?”

“I don’t know what you’re—” But I did know, didn’t I? I knew the way I had known that Adam was in the hydroponics garden. I knew because we always knew when we were near each other. The pheromones we put off, however hard it was for our human bodies to detect them, were unmistakable.

Slowly, I turned to face Anna, who hadn’t responded to our presence in any way. She was still staring at the ceiling, her bare skin humping up into goose bumps as the air-conditioning rolled over it. She didn’t seem to know that we were there, or maybe it was just that she didn’t care.

My mouth was terribly dry, and the drums were pounding in my head. I licked my lips, trying vainly to moisten them, and whispered, “I didn’t think anyone could be this cruel.”

“What did he do?” moaned Adam.

Anna turned her head and looked at us.

I froze. Having her staring at me was like being eye to eye with an alligator, or some other ancient beast that didn’t care what I wanted and wouldn’t care if I ceased to exist completely. She didn’t blink. Maybe that was an optical illusion, something my increasingly baffled mind was adding to make the situation even more alien, but I didn’t think so. Dr. Banks had brought her to us. He said she needed to be monitored, but he could have done that at SymboGen; he wouldn’t have brought her here if there hadn’t been something terribly wrong with her, maybe with the interface between her tapeworm and human nervous systems. That was the most important connection a chimera had, and if it wasn’t working properly, then she wasn’t working properly.

Dr. Cale’s wheels squeaked softly as she rolled herself over to stop next to me. She was no longer covering her mouth, and her tears were no longer contained: they rolled down her face unchecked. Bit by bit, her expression transformed from grieving mother to furious scientist. It was a swift, terrifying change. “That bastard,” she said, tone almost wondering, like she couldn’t believe this was happening. “I don’t believe him. How could he do this? How could he come here, having done this, and expect me to help him?”

“I don’t understand,” said Nathan. He moved to stand behind me. I tilted my head just enough to see the furrowed line of his brow. He really didn’t get it. Just this once, I had reached a conclusion before he had.

I would have expected it to feel good, or at least to feel better than this. Instead, I felt sick. I would have given anything to have reached the wrong conclusion, but I hadn’t: I could see it in Dr. Cale’s face.

“This is Tansy,” I said quietly. “This is why we couldn’t find her. Because Dr. Banks had her the whole time. She never got away from SymboGen.” I indicated the pale, naked girl on the cot, who was still staring at us with her dead-looking eyes. “He took her, and he used her, and now he’s brought her back to us, but I don’t know why.”

“That’s not Tansy,” said Nathan. “Tansy looks completely different.”

“Not to a chimera she doesn’t,” said Dr. Cale. Her hand snaked out surprisingly fast, grabbing hold of my wrist. “Are you sure, Sal? It’s not just a culture, like the ones we took from you? It’s actually her core implant?”

“Yes,” said Adam. He darted forward, again moving faster than I could react, and grabbed hold of Anna’s hand. He held it the way that he always held mine, the way that he used to hold Tansy’s: tight and close and counting on the other person to cling tight, keeping him where he was.

Anna’s fingers stayed loose and open, not closing around his. He might as well have been grabbing for a corpse. In a way, that was exactly what he was doing.

“I don’t know,” I said, shaking my head until my hair whipped against my forehead like a hundred tiny, stinging lashes. “I don’t… I’m not as good at picking up on that sort of thing as Adam is. But the minute I saw her, I wanted to protect her, even if it meant protecting her from you. I normally only feel that way about Adam.”

When Nathan and I had first followed a weird set of instructions to Dr. Cale’s old lab in the bowling alley, we’d been met by a girl with short blonde hair, heterochromatic eyes, and a tendency to make cheerful death threats every six words. That was Tansy. She was the experimental subject that came after Adam, grown and cultured in the lab just like he was, and she’d been his first sister, the one who kept him safe from the world back when most of the world had no idea that people like him, people like her, people like me could exist. Tansy had acted like a thug and reacted like a heroine, and if that wasn’t one of the best combinations I’d ever encountered, I didn’t know what was.