“I saw them bring Dr. Banks and the new girl in,” he said, taking a step forward, out of the trees. As sometimes happened with Adam, he looked infinitely younger than me in that moment. “I wasn’t supposed to be there, and Mom told me to get to work as soon as she realized that I was watching, and I didn’t want to go. I wanted to tell Mom no, because the new girl needed me so bad. It was like… it was like the need was just rushing off her, like water out of a hose. And I started to think that maybe that’s why you like me. Because need rushes off me, and you don’t know how to get out of the way.”

“I think Dr. Cale was right when she theorized that we had a pheromone connection, just like the sleepwalkers do,” I said, choosing my words with exquisite care. “We’re their cousins, so it makes sense that we’d have some of the same systems in place to make sure that we stayed in contact with each other, and that we looked out for each other. And yeah, it was sort of a surprise to me—I always just figured I wanted you to be safe because I cared about you. Now it turns out that there’s also a chemical component, probably generated automatically when you’re under stress or whatever.”

This wasn’t helping. Adam was starting to look more concerned, and if I didn’t change tactics soon, he was going to retreat into the avocado trees and I was never going to catch him. I sighed.

“But Adam, that’s just the initial pang of alarm, that’s like ants leaving chemical trails for one another. We’re not ants. We’re not even sleepwalkers. We can think. We can feel, and we can form social bonds. I don’t care about that girl as a person. Yes, when I’m in the room with her I want to protect her and keep her safe, and I figure that’s probably a good thing from a species perspective, since it’s better if we want to protect each other and not kill each other.” I was babbling. But Adam wasn’t retreating anymore, and I’d take that. “Only see, I do care about you. I want you to be happy. I like it when we just sit and don’t talk to each other because we’re both doing stuff. You’re my brother and I love you, and she’s just some girl who happens to be the same species that we are.”

“Really?” Adam finally stepped out of the shade of the avocado trees, his eyes so wide that I could have tripped and fallen into them. “You really think I’m your brother?”

“Only one I’ve ever had.” Unless you counted Sherman—and he, like Anna, was just someone who happened to share my species. He didn’t deserve to be a part of my family. He didn’t deserve to be anywhere near my family.

“What’s going to happen now that she’s here?”

“I don’t know, but that’s part of what I wanted to talk to you about. Dr. Banks says she integrated while her host body’s consciousness was still present and aware.”

Adam’s eyes went even wider, the whites appearing all the way around his dark brown irises. “She’s a fully integrated sleepwalker?”

Because that’s what we were all dancing around: that was why her existence was such a concern. If one tapeworm could integrate with a living, conscious host, so could another, and another, until the entire shape of the enemy changed. We could be looking at a fight that went from intellect against mindless hunger to intellect against intellect—and for me and Adam, it would be a fight against our own kind.

I’d always assumed I would side with the humans, no matter what happened, because the sleepwalkers were destructive and terrible. So was Dr. Cale, in her own way, but at least she cared about saving lives, while Sherman didn’t seem to care about anything beyond himself. The possibility of living, active integration changed everything, and from the way Adam was looking at me, it changed everything for him, too.

I looked into my brother’s eyes, suddenly aware of just how deep that familial connection went, and had no idea what we were going to do next.

Adam was like me—a chimera of human and tapeworm, a dead body piloted through the world by an invertebrate. He was also unlike me, because he hadn’t happened naturally, and he had never believed himself to be a human being. When the war began, there had never been any question of which side he would be on: the only humans he knew were the ones who worked for his mother and fully accepted his existence. Liking it was something else altogether. Adam’s sheltered upbringing meant that he wasn’t quite as good as I was at seeing the way they sometimes looked at us, like we were a problem that needed to be solved after the bigger, more immediate problems—the sleepwalkers, all the humans who were dying—had been taken care of. But I could see it. I could see it all too well.

For every person like Nathan or Dr. Cale, who honestly didn’t care what species we were, there was someone like Daisy, who couldn’t relax around us, or Fishy, who saw us as one more symptom of the world’s devolution into a fantasy. We weren’t real to them. We weren’t people.

“It sounds like that,” I said. “I think she may be something else, though. I mean, aren’t sleepwalkers what happens when an implant just decides to take over? The way Dr. Banks was talking, she happened in a lab setting. So I don’t know for sure.”

“There’s only one way to find out,” said Adam. He slipped his hand into mine, looking at me hopefully. Once again, I was struck by how young he seemed. He was the first chimera, the oldest member of our race, and sometimes I felt like he was going to be my baby brother forever. “Can we go meet our sister?”