But not for Nathan. I had never mourned for Nathan, because the part of me responsible for managing the boundary line between the human world and the hot warm dark knew that losing him on top of everything else would have thrown me so deep into the darkness that I would never have come up again. I admired my own ability to care for myself, and I clung to my brother, and I cried.

Finally, after enough time had passed that each of us was confident that the other person would continue existing even without skin contact to keep them in the world, Adam started to unlatch his arms. I did the same, letting him go and stepping backward, into the comforting solidity of Nathan’s supporting hand. He wouldn’t let me fall. No matter how bad things got, Nathan would never, never let me fall.

“Hi, Sal,” said Adam, reaching up to wipe the tears from his cheeks before he beamed at me. “You came back. I didn’t think you were going to, but you did.”

“I’m sorry it took me so long.”

Adam shrugged, visibly dismissing the delay. It had taken a long time, but that was over now: that was done, and I was finally home where I belonged. That was all that really mattered as far as he was concerned. “Mom said you were coming, but I wasn’t sure whether she knew for sure that you would still be you. Or still be alive. You could have been like the cousins that they bring in from the field sometimes. They’re not here anymore.”

I glanced at Nathan. “I don’t know what you mean by that.”

“We’ve been harvesting sleepwalkers from the local population,” Nathan said, and to his credit, he looked both sad and determined as he spoke. “We have to know how the implants are mutating, and unfortunately, that’s the only way for us to track what’s happening out there. We try not to hurt them more than we absolutely have to. But we don’t bring back live specimens.”

Intellectually, I knew that was the right way to go about things. After all, sleepwalkers were irrationally hungry and capable of pushing their stolen bodies to dangerous extremes. Bringing them into the lab alive would endanger everyone. At the same time, these were my cousins, and I felt strange about the idea that we were going out and collecting them as scientific specimens when they weren’t actually hurting anyone.

“Oh,” I said softly.

Adam’s smile returned, weaker than before, as he moved closer and reached for my hand. I let him take it, appreciating the feeling of his fingers lacing through mine. He was smarter than me in some ways. Dr. Cale had been in charge of his schooling, and hadn’t been trying to make him think that he was human. He was better-read than I was, and educated at a much higher level overall. He understood science stuff that went straight over my head, leaving me puzzled and surrounded by people who might as well have been speaking Greek. In other ways, mostly having to do with social interactions, he was a little behind me. He liked to remind himself that he had skin. The best and easiest way to do that was with hugs and holding hands.

Nathan took my other hand. I looked from one of them to the other, listening to the drums that pounded in my ears and considering how different they were, and how similar. Dr. Cale’s two sons.

“This way,” said Adam, and—tugging on my hand—started leading me deeper into the lab. I let him, holding tight to Nathan so that he would come along with us as we stepped into the strangely familiar, strangely modified maze of free-standing work stations, cubicle walls, and tiny research bays that Dr. Cale and her people had carried with them from the lab back in Clayton. As we walked, I finally started recognizing people. Not everyone, but a researcher here and a lab assistant there would seem familiar, and then they would stop what they were doing to straighten up and stare at me like they were looking at a ghost. These were the people who had already written me off as lost forever, and were now faced with the fact that sometimes dead things aren’t so dead after all.

We stepped around a corner and into a small “meeting room” carved out of the room’s wide expanse by the careful placement of filing cabinets, desks, and bright pink cubicle walls that had probably been stolen from the administrative offices somewhere in the building. Dr. Cale was there, transcribing something in a small notebook. We stopped. Nathan cleared his throat.

“We found her,” he said.

Dr. Cale raised her head. For a moment—no more—her expression was completely unguarded, and I could look into her unshuttered eyes and see just how exhausted she really was. There were small wrinkles in the skin around her mouth and at the corners of her eyes that hadn’t been there a month ago. Then the walls came crashing down, and it was smiling Dr. Cale once more, as inscrutable and untouchable as ever.

“Hello, Sal. Did you enjoy your vacation?” she asked. “You could have sent a postcard or something, you know. Just to let us know that you were alive out there, and that we could stop worrying quite so much about you.”

My hands were still full, with Nathan clasping one and Adam clasping the other, and so I just shrugged and said, “Sherman wouldn’t give me a stamp.”

To my surprise, Dr. Cale laughed. “Oh, that’s a good one. I’ll have to remember that. What happened?”

“Um. From the beginning, or from when I woke up in the empty house where I found the cellphone, or…? There’s a lot to tell, and I don’t really know where I’m supposed to start telling it.”

“She’s tired, Mom,” said Nathan protectively. His hand tightened on mine. “Sherman’s been taking tissue samples from her.”