“You were never afraid of the monster in your closet, though,” said Dr. Cale. There was a brief warmth in her voice, like she was remembering what it was like to be the woman she’d been when she was just Nathan’s mother, and not a renegade genetic engineer hiding from the world’s largest biological medical company.

That thought looped around itself so many times that it managed to confuse even me. I shook my head, trying to clear it, and looked down at the blue and black cover one last time. Even knowing how the story ended didn’t make the children seem any less terrified, or make the painted forest any less dark. If anything, knowing what the book was actually about made it worse. The children were looking for the broken door. By finding it, they would get their answers… and they would give up their humanity forever.

“No,” said Nathan. His tone was much more subdued than his mother’s. I looked up again to find him studying Dr. Cale, a grave expression on his face. His smile was entirely gone. “I knew the monster in my closet would take care of me. The monster would always love me, no matter what I did. The monster would never leave me.”

I suddenly felt like I shouldn’t be here, witnessing this. I shrank back in my chair as Dr. Cale’s face fell, all the light going out of her. “Nathan…” she began.

Nathan talked right over her, asking, “Did you have any contact with Dad after you left us? Did he tell you about the times I ran away, trying to find the broken doors? I knew my monster would be on the other side, and she would love me.” He straightened, suddenly seeming to realize where we were. “We’re pretty much done here. I need to get Sal home. Her parents will be worried about her by now, and I’m supposed to work a late shift at the hospital. We’re slammed right now.”

“It’s just going to get worse as the implants continue to assert themselves,” said Dr. Cale. “We need to work together on this, Nathan. You can’t just walk away and pretend you don’t know what’s going on.”

“I’m not going to, Mother, but I’m also not going to stay here. This isn’t the side of the broken doors that I belong on. Once it was, maybe. If you’d come to me when I was still looking for you behind every corner. But not now. I live in the real world now.” Nathan walked over to where I sat, offering me his hand. I took it, and he tugged me to my feet. “It’s time for us to go.”

“Thank you for sharing what you know, Dr. Cale,” I said, hugging the book to my chest like I was protecting it. I was, in a way; Nathan wanted to take it with us, and I didn’t trust Dr. Cale not to try snatching it away from me if I gave her the chance.

She didn’t move to take the book. She didn’t move at all. She just looked at the two of us, an odd sort of sorrow in her eyes, and said, “When Simone got that published, mine was one of the very first copies she gave to anyone. She said it would help me teach my children how to be safe. You were a baby at the time, Nathan. You probably don’t even remember Simone.”

“No,” said Nathan, putting his arm around my shoulders. “I don’t.”

“She was a little woman. Always sick, all the time, no matter what she did. See, when we were young, parents thought you had to keep the world so clean it was sterile if you wanted to protect your children. Her immune system never learned to deal with anything it didn’t recognize. She died before you were old enough to get to know her, but I think you would have liked her.” Dr. Cale looked toward the charts on the wall, showing the development and life cycle of her precious D. symbogenesis. “You always wanted to know why when you were a little boy. Why this and why that, and why, why, why until I thought your father was going to lose his mind. I’ve been asking myself for years why this was the project I had to join. Why was this the one thing I had to do, out of everything that I could have done, out of every opportunity I had.”

“Did you figure it out?” I asked.

“Yes.” Dr. Cale turned to me, smiling slightly. “I did it for Simone. She might have died anyway—no one can predict the future, or we’d find ourselves in a lot less hot water—but she wouldn’t have died the way she did, of an immune system that simply refused to keep her alive any longer. I did it because I wanted to give you and your loved ones a better future, Nathan. And yes, I did it because I could. Isn’t that the justification used by every scientist who made something wonderful, only to discover that they’ve made something terrible? ‘We did it for science.’ ”

“Science doesn’t always play nicely with the other children,” said Nathan.

Dr. Cale sighed. “So true. Come on, give your mother a hug—and for God’s sake, be careful out there. I still don’t know how D. symbogenesis is accomplishing all this outside of lab conditions, and I won’t know until I’ve had more opportunity to study the afflicted. There’s no telling what could happen.”

“Okay, Mom,” said Nathan. He squeezed me quickly before walking over to hug his mother, who returned the gesture with all the fervency of someone who had never expected to have this opportunity again. After a few seconds of that, Nathan melted into her embrace, and the two of them just held each other, long enough that I started to get uncomfortable. I looked away, studying the room instead.

In addition to the charts and graphs on the walls, there was a corkboard with a few tacked-up photographs, including a grainy shot of Nathan that had clearly been taken with a distance lens. There was one picture of Adam and Tansy sitting together, she with a shaved skull and a bandage taped to the side of her head, he with the doting smile of an older brother.