Symbiont

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Chapter 1 SEPTEMBER 2027

Dr. Cale’s lab might have been concealed in an abandoned bowling alley, but she’d clearly never seen that as a reason for her equipment to be anything less than state-of-the-art. The MRI scanner was kept in a private room, and was as elaborate and complex as anything they had at SymboGen. I tried to focus on how surprising it was to see a piece of machinery that complicated in a place like this as I shed my clothing on the floor and allowed Nathan to help me into the scanning bed. I’d been through this process before. It made it easy for me to lie still and close my eyes, pretending that none of the last few weeks had happened; that everything was still normal, that I was still me, and not the thing that I was desperately afraid I was becoming. Or worse, the thing I was even more afraid I had been all along.

The MRI came to life around me, the hammers and clangs of the vast machine blending with the insistent pounding of the drums in my ears until there was nothing else: just sound, vibrating through my flesh, anchoring itself beneath my sternum. My flesh, my sternum. Ownership was so easy to claim, but did I have any right to it?

Please, please, it’s something else, I thought, lying to myself one last time while the option was still open to me. Please, it’s not what I think it is. Please, there’s another answer…

The MRI gave one final pulse as it shut off. The sudden silence was deafening, only slightly lessened by the hum of the automated scanning bed sliding back out into the room, where the chill air raised goose bumps on my arms and legs. I grabbed a lab coat off the side of the machine, pulling it on as I climbed back to my feet. It didn’t do much to cut the chill, but I didn’t want to spend the time to pick up my clothes.

Nathan was seated at the monitor, the display reflecting off his glasses as he pulled up the first images of my insides. I stopped behind him, putting my hand on his shoulder. He put one of his hands over mine, using the other to continue working the mouse.

My abdomen should have been occupied by a lot of things: organs, scarring, and the pasty white mass of the SymboGen implant, which would naturally gravitate toward the base of my digestive system. It wasn’t there. The blood tests had been telling the truth: there was no residual tapeworm protein in my blood because there was no tapeworm in my digestive system. Nathan clicked to the next image. It wasn’t in my lungs, either. The image after that proved that my spinal cord was clean.

His fingers tightened on mine. I think that if I had told him to stop then, he would have, and we would both have walked away with the question unanswered. I didn’t tell him to stop. I needed to know. He did too, if only so that we would both be standing in the same place for once.

Nathan clicked the mouse. Everything changed.

The image showed the inside of a human skull, normal save for some small remodeling of the bone toward the back. The brain was there, lit up in bright colors that represented activity during the MRI. The tapeworm was there too, showing up as loops of nonreactive white against the bright neural map. It was deeply integrated, slithering in and out of brain tissue. But I’d known that before I’d seen the image, hadn’t I? I’d figured it out when I met Adam and Tansy, when I was faced with the reality of their existence. When I’d started to care about them, despite their monstrous origins.

Even knowing what they were hadn’t been strictly necessary, had it? Sherman was a tapeworm too, and I had always liked him best, out of all the people at SymboGen. From the moment I’d met him, I’d liked him. If I’d had even the slightest clue that he was a product of Dr. Cale’s lab, that would have given me the information I needed. When I met a tapeworm, when I met somebody like me, I liked them. I couldn’t help myself. Even if I’d wind up disliking them later, I started from a place of “you are family.”

So yes, I’d figured it out, and then I’d locked it away, because I hadn’t wanted to admit it to myself. Admitting it would make it real. Only I guess pictures could do the same thing, because I didn’t even try to deny that the image on the screen was me.

For the first time in my life, I was looking at who—at what—I really was.

I was never Sally Mitchell after all.

“The protein markers couldn’t cross the blood-brain barrier in a detectable form,” said Nathan. His voice was soft, like he was afraid anything louder would startle me. He wasn’t wrong. “It’s why we couldn’t detect…” He stopped, obviously unsure how to finish the sentence.

There was no kind way to do it. “Honey, you’re not human” isn’t a conversation either of us was equipped to have. “Mom was right,” I whispered. She’d called me a stranger, and it had hurt, but it hadn’t hurt as much as it should have, had it? No, because I’d already figured out the same thing she had: that I wasn’t Sally. Her daughter died in the accident that put her in the hospital. I was a stranger living inside her baby’s skin. I was a stranger to the entire human race. “Oh, my God. Nathan. Do you see…?”

“It doesn’t change anything,” he said, suddenly fierce. He let go of my hand as he stood, pushing the chair out of the way before he turned and wrapped his arms around me. He pulled me against him, holding me so tight that I was almost scared he would crush me. I put my arms around him in turn, doing my best to hug him just as hard. Voice still sharp, he said, “Do you understand me? It doesn’t change anything.”

I raised my head and looked over his shoulder. Dr. Cale had parked her wheelchair in the doorway. She was sitting there watching us, an expression of profound regret on her face. I wouldn’t have believed that she was capable of looking so sad, but in that moment, she managed it, and in that moment, she looked like her son. Coloring and race didn’t matter, not when stacked up against that expression.

So much of the way she had always interacted with me made sense now. So much of it still needed to be made sense of. “No,” I said. “It changes everything.” The broken doors that Dr. Cale had spoken of so often were open now; I could no longer pretend that they were just a children’s story, something I could safely forget about or ignore.

I looked back to Nathan, raising my eyes to his face and searching for any sign of rejection or revulsion. I didn’t want to leave him, but I didn’t want to make him stay with me if he couldn’t deal with the reality of what I was. I wasn’t sure I could deal with the reality of what I was—the calm I was feeling was probably shock, and would pass, replaced by hysteria. Better to make my choices now, when I could trust myself, than to let it wait until I was no longer thinking clearly.

How was I thinking at all? A tapeworm, no matter how cunningly engineered, didn’t have the size or complexity to think human-sized thoughts—but I managed it somehow. I had to be… the tapeworm part of me had to be driving Sally Mitchell’s brain, using it as storage somehow, like a person uses a computer. The thought made my stomach clench, and so I focused back on Nathan, who was safe; Nathan, who had never known Sally, but had fallen in love with Sal, with me, with the girl who had helped her injured sister into his office. He’d never batted an eye at any of my idiosyncrasies. Sally’s family had learned to love me when I replaced their daughter. Nathan had never needed to forget a person I could never be. That had always been so valuable to me. I was starting to understand a little bit more about why.

He met my eyes unflinchingly, and all I saw there was concern, and hope, and yes, love. He looked the same as he always had: black hair, brown eyes behind wire-framed glasses, golden-tan skin, and a serious expression that could spring into a smile at any moment. I didn’t see any fear or dismissal, or even dismay, in that face. I blinked.

“You knew,” I said, bewildered. “How did you know?”

“I told him.” Dr. Cale sounded tired. I pulled away from Nathan and turned to face his mother, who was pale where he was dark, from her sun-deprived skin to the watery blue of her eyes and the ashy blonde of her hair. Her shoulders sagged as she looked at me, and she said, “Back in my lab, when you were asleep on Adam’s cot. I thought he should… I’m sorry, Sal, but I thought my son should know that his girlfriend wasn’t entirely human. You clearly weren’t ready to have the same conversation. Perhaps it was wrong of me.”

“I think maybe it wasn’t,” I said slowly. “I wasn’t ready to know this yet. I wasn’t letting myself know this yet.” I looked down at my hands. “But I was going to figure it out.” I had already figured it out, and then locked the knowledge away from myself, as if that sort of thing had ever done any good. Once the signs had been placed in front of me, they had been too easy to follow. I would have followed them again, and maybe then, I wouldn’t have been able to make myself forget. “I needed Nathan to know before I did. I needed him to have time to come to terms with it. Because if he’d left me then…”

If Nathan had been having his own freak-out at the same time I was having mine, I don’t know how I would have gotten through finding out the truth about myself. Having him pull away from me then—even temporarily—would have devastated me. Here and now, in this lab, with Tansy missing and Sherman alive but suddenly my enemy, losing my humanity was a huge step toward the abyss. Nathan had been able to place himself between me and that long, final fall, and he’d only been able to do it because he’d already known what I was.

Dr. Cale nodded. “I’m glad you see it that way. That’s what I was hoping for.” She paused, watching me carefully before she continued: “I know you’re in shock right now, and I know we’ve all had a difficult day, but do you think I could have that thumb drive?” She grimaced. “I hate to ask you. I hate to even be here right now. You deserve this moment. But I need that data.”

My eyes widened. “I forgot.” I had been refusing to give her the thumb drive full of information stolen from the SymboGen computers until she gave me the answers I thought I wanted. But then I’d been distracted by the need for blood tests and MRIs and then… “I’m sorry.”

“It’s all right.” Now the glimmer of a smile touched her lips. “You had other things on your mind.”

The words sounded faintly unreal, like she was quoting them from a book or movie, something that showed how an ethical mad scientist would behave. I pulled away from Nathan entirely, bending to rummage through my discarded clothing until I found the thumb drive in the front pocket of my jeans. I walked over and held it out to Dr. Cale, who took it without commenting on the fact that I was still wearing nothing but an unbuttoned lab coat. Between Tansy, Adam, and… and Sherman, she must have gotten used to people whose sense of modesty was somewhat less developed than the norm.

“Thank you, Sal,” said Dr. Cale, taking the little plastic rectangle gently from my fingers. “You have no idea how much we need this data.”

“What is it, exactly?” I asked. “Tansy said it would explain how some of the sleepwalkers were integrating more quickly with their hosts…”

“It’s easy to forget sometimes that Steven Banks is a genius,” said Dr. Cale, still looking at the thumb drive. There was honest regret in her voice. “He blackmailed me into working for him, but the only reason he could was because I knew I wouldn’t be doing the heavy lifting alone—he’d be there to help, and to carry it on when I couldn’t go any further. It’s easy to sit here and say, ‘I did it, it was all my fault; I am Frankenstein and this is my monster,’ but D. symbogenesis is Steven’s baby as much as it is mine. Maybe more, by this point, at least where the commercial models are concerned.”

“Meaning what, Mother?” asked Nathan.

“Meaning he continued the work after I left; he continued altering the genetics of the different strains and families of implant, looking for that perfect mixture of form and functionality. He didn’t toss up his hands and say, ‘Well, Shanti’s gone, better throw in the towel and stick with what we have.’ He innovated. He improved. And what we have here, on this little piece of hardware, is a collection of those innovations.” Dr. Cale raised her head, and I almost recoiled. I wasn’t human, but neither was the light burning in her eyes: bright and cold and unforgiving. “Now that we know what he’s done, we’ll know how to undo it. So thank you, Sal. Thank you both. You’re welcome to stay here for as long as you like. I recommend you consider making your residency permanent.” On this grim note, she placed the thumb drive carefully in her lap, turned herself around, and rolled out of the room. She didn’t look back once.

Nathan put his hand on my shoulder, stepping up beside me. The warmth of his body was reassuring. “Are you all right?” he asked.

I tried to answer him—I honestly did—but all that came out was a high, anxious squeal of laughter, like the sort of sound a rat might make if it was caught in a trap. Something wet was on my face. I raised my hand to touch my cheek, and found tears there, flowing freely from both eyes. My narrow window of calm had apparently passed.

I tried again to answer him, and this time there was no sound at all. The drums were back in my ears, and they grew louder as, with a great rushing roar like water pouring over a cliff, the dark crashed down and took me away.

One advantage to passing out repeatedly in the same place: you’re more likely to wake up somewhere familiar. I opened my eyes and found myself looking at the ceiling of Dr. Cale’s lab, lying on the same narrow cot that had served as my bed the last time I had fainted. Only one light was on, and it was behind me, casting the room into the sort of deep shadow that never happens naturally. I sat up, dimly aware that I wasn’t alone.

“Hello? Who’s there?” I frowned into the darkness in front of me. “So you know, I’m having a really bad day, so I’d appreciate it if you could move straight to threatening me, or making weird noises, or turning out to be on the other side of some massive ideological divide that’s going to shape the future of the human race.”

“I don’t think we have any massive ideological divides,” said Adam. He slipped out of the shadows to my left, frowning bemusedly. “Are we supposed to?”

“Oh,” I said. “Hi, Adam.” The drums started up in my ears again as my heart began to hammer. Adam was one of Dr. Cale’s human-tapeworm hybrids; the first, to hear her explain the situation. He was the oldest of us in the world. Everything I was experiencing was something he had experienced before me… and also not, because he had never spent a moment thinking he was anything but what he was. When he’d opened his eyes for the first time, it had been onto a world filled with people who knew his origins, accepted them, and didn’t try to make him into something else.

That must have been nice. I couldn’t even imagine how nice it must have been. Dr. Cale had created him intentionally, combining samples of her first-generation D. symbogenesis worm with a brain-dead boy whose parents had basically sold him to her in exchange for escaping his mounting medical bills. I didn’t know what his body’s name had been before Adam took possession. So far as I was aware, he didn’t know either. It had never really mattered. That boy was gone, and Dr. Cale had never known him. She’d raised Adam without any shadows that wore his face to follow him around and make him feel bad for existing.

“Where’s Tansy?” He took another step toward me, the light revealing more of his features. He was skinny and pale, with the sort of face that was practically designed to blend into crowds, just conventionally attractive enough not to stand out, too essentially plain to snag in the memory. He had blue eyes and sandy brown hair, and even though we didn’t look a thing alike, something deep in my core was telling me that he was my brother: more my brother than Joyce had ever been my sister. Adam was family. And family had to stick together.

That feeling had always been there, I realized, but it was getting stronger from the combination of proximity and understanding. I wasn’t in denial anymore. I could accept all the parts of what I was—and that included my brother.

Adam was also frowning, confusion and dismay becoming more pronounced with every second that passed without my giving him an answer.

“She went with you,” he said, his tone implying that I might have forgotten—like I might have been distracted, or hit my head when I fell down and hit the floor. “That’s what Mom said. She said that Tansy was going to get you out of SymboGen so that you and Nathan could both come home, and we could finally be a family the way that we were supposed to.”

The pounding of the drums didn’t lessen, but it was joined by another, less pleasant sensation: my stomach, slowly converting itself into solid ice. If Adam was my brother, Tansy was my sister. Oh, God. Did my sister die to save me?

No. Not possible. Tansy was too mean to die that way. “Tansy was… she was there, yes. She’s the reason I got out of SymboGen. I don’t think I could have escaped without her.” That wasn’t quite true. I knew that I wouldn’t have escaped without her. Tansy had been the motive force driving my escape from the building, and it was only her willingness to stay behind that had bought the time Nathan and I needed to get to the car. Without Tansy, I would have been a prisoner, or worse.

And Tansy wasn’t here.

Adam looked at me, frown deepening into something sharp. “That’s what Tansy does,” he said. “She doesn’t think much before she helps other people. Or hurts them, sometimes. She says it’s because of the parts in her brain that aren’t functioning optimally. I think she’s trying to get hurt badly enough that Mom will transplant her into a new host, but I don’t want that to happen. She wouldn’t be Tansy anymore if that happened. She’d be someone else.”

I blinked. “Wait—that’s a thing that Dr. Cale can do? She could just scoop you out of the body you’re in and put you into a different one?”

“Sort of,” said Adam. “She says it becomes a question of nature and nurture, because memories don’t carry over, just core personality and epigenetic data, and—wait. Are you trying to distract me? Where’s Tansy, Sal? Why didn’t she come back here with you?”

I took a deep breath, which barely warmed the ball of ice sitting in my stomach, and said, “She stayed behind, Adam. There were a bunch of sleepwalkers—more than I’ve ever seen in one place—and they were going to hurt me, and Nathan. So Tansy stayed behind to fight them. She bought us the time that we needed to get away.” She’d gone down under a wall of bodies, all of them biting and clawing at her like the fact that she was only developmentally one step removed from the sleepwalkers didn’t matter—and maybe it didn’t. I didn’t feel any kinship to them, and never had, but with every minute that passed, I was feeling more as if she and Adam were, and had always been, family.

I really should have seen it sooner. Neither he nor Tansy had ever upset me the way the sleepwalkers did, even though they should have. Especially Tansy, whose methods of communication were brusque at best, and dangerous at worst. I’d already known on some level that we were the same, and it was easier to be forgiving of family. That’s what family was for. I didn’t know how I knew that. I probably shouldn’t have, given my experiences with Sally’s family. But I knew.

“Why didn’t you stay and help her?” asked Adam blankly.

“I couldn’t. I don’t know how to fight, and the information I had… I had the information Dr. Cale needed. If I’d stayed to help Tansy, the information would have been lost, and then Dr. Cale wouldn’t have been able to continue her work.” The knot of ice in my stomach seemed to be loosening a little.

“Oh.” Adam mulled this over for a few moments, looking even younger while he did. Maybe that was one of the functions of the tapeworm-to-human interface. I had perceived a certain childishness about Tansy, and my parents—Sally’s parents—used to comment on the fact that I looked young and lost when I was thinking. It was one more thing I didn’t share with their original daughter, who had never been much for stopping to think about things, and certainly wouldn’t have looked lost while she was doing it.

It hurt a little to realize that I didn’t entirely think of them as my parents anymore; not the same way I had only a few weeks before. They would always be a part of who I was, but I no longer felt the need to try to make them love me, and that felt like the sort of bond that should have taken longer to break. Maybe it was different when the bond had never fully formed. They’d always be important to me, but they hadn’t made me.

“Well, I guess she’ll tell me what happened when she gets back,” said Adam finally, and walked over to sit down on the edge of the cot, looking at me with wide, guileless eyes. “Are you feeling better? You sure do faint a lot.”

“I get startled a lot,” I said, smiling despite myself. “What about you? You’ve never fainted? Not even once?”

“A few times, when I first woke up,” he said. “Mom says it’s because some of the blood vessels feeding into my brain were compromised during my surgery, and they needed time to recover.”

I wondered absently if I might be dealing with something similar. It didn’t seem likely. Any weak blood vessels would have been found and fixed by SymboGen years ago. I was just dealing with plain, old-fashioned shock, and that was actually a little reassuring: at least something about me was plain and old-fashioned.

“Oh,” I said. I took a deep breath. “Adam, can I ask you something sort of personal?”

Adam sat up a little straighter, going still. “Yes,” he said, after a moment’s hesitation. “You can ask me anything.”

“I…” I stopped. I didn’t know how to frame the question that came next. I didn’t even know how to start. “Did you know I wasn’t human?” seemed too accusatory, and “Have you noticed anything strange about me?” felt almost, well, coy. I finally settled for “Do you like being you?”

A wide smile spread across Adam’s face, tight-lipped, so that his teeth were concealed. I realized with a start that he’d never shown his teeth when he smiled at me. That was a mammalian gesture, and the part of him—the part of me—that drove those reactions wasn’t mammalian. “I love it,” he said. “I have hands, and feet, and fingers, and eyes, and it’s wonderful, Sal, it’s just wonderful. There’s so much world. I could live a hundred years and never see all of the world that there is to see. Mom gave it to me. You know? Mom made it so I could walk and dance and sing and run bacteriological cultures for her and it’s just wonderful. You know that, right? That life is wonderful.” His smile faded, replaced by a look of grave concern.

I cocked my head, studying him. “You knew as soon as you met me that I was like you, didn’t you?” I asked. “That’s why you’re trying so hard to convince me that life is wonderful. Because you want me to love it the way you do.”

“You already do,” he said earnestly. “You wouldn’t have come looking for the broken doors if you didn’t love life. Curiosity is what it looks like when you’re in love with the world.”

“Did Dr. Cale teach you that?” I asked.

Adam nodded. “Mom says you know someone is getting tired of living when they stop asking questions.”

“You didn’t answer my question.”

“I know.” He looked down at his hands. “I knew before you came here. Mom told me and Tansy all about you—Tansy so she’d know who she was supposed to be keeping track of, and me because she wanted me to know about both my—” Adam cut himself off midsentence, glancing up almost guiltily.

I offered him a wan smile. “Both your sisters,” I said. “She wanted you to know about both your sisters.”

“Yeah.” Adam’s relief was palpable. “She said you’d come find us one day, because you were her daughter, and her daughters were always going to be curious. It’s in the way we’re made.”

“I guess I have a lot to learn. You’re going to have to teach me, you know. I don’t really know much.”

Adam abruptly spread his arms and lunged forward, moving so fast that I didn’t have a chance to react before he was hugging me hard, his head resting on my shoulder and his arms locked around my chest. I stiffened until I realized what was going on, and then I relaxed, bit by bit, and even raised my own hands to return the hug as best I could.

“I’m going to be the best brother, you’ll see,” he said. “I’m going to teach you everything, and we’ll both be here when Tansy comes home, and then she’ll like you, because you’ll be with us, not living all by yourself. We’ve both been so worried about you!”

The funny thing was, I believed him… and I wanted him to be the best brother. I wanted a family, a family that was mine, not Sally’s castoffs and hand-me-downs. I breathed in and he breathed out, until bit by bit our breathing synchronized, and the pounding of the drums in my ears quieted, becoming nothing but the distant thudding of my heart. Adam let go, sitting back on his haunches. I dropped my hands back to the cot, just looking at him. I didn’t know what to say or how to say it; there were no words.

“Are you okay?” he asked solemnly.

“I don’t know,” I said. “This morning, I thought I was a human being, and I thought my friend Sherman was dead, and I thought… I thought a lot of things. Now everything is changing, and it’s changing so fast that I can’t really keep up. So I don’t know if I’m okay.” I paused. “But I think I’m going to be.”

Adam nodded. “Going to be is almost as good as is,” he said. “I’ll be here. I’ll help as much as I can.”

I smiled. “See, that right there makes me closer to okay. I’m glad I don’t have to do this alone.”

“Me, too.” He climbed off the cot, bare feet slapping the tile floor. “I need to go tell Mom you’re awake—she asked me to let her know as soon as you woke up, but I thought it was more important that we talk a little bit first. That was right, wasn’t it?”

“Right as rain,” I assured him. I peeled back the blanket, finding that I was as barefoot as Adam, although someone had dressed me in my shirt and jeans while I was unconscious. I stuck the fingers of one hand under my waistband, and decided that Nathan had dressed me. I couldn’t see Dr. Cale remembering to tell her interns to put my underwear back on. “Why don’t I come with you?”

This time Adam’s smile was almost bright enough to light the room.

There were more technicians around than I had seen on previous visits to Dr. Cale’s lab. They swarmed around the equipment like ants, some of them checking cultures or typing at workstations, while right next to them others broke down shelves and packed glassware with an eerily silent efficiency. Adam led me unflinchingly through their midst, his hand clasped tightly around mine, like he had absolute faith that nothing here could hurt either one of us. A few of the technicians turned as we passed, and while they seemed perfectly comfortable with looking directly at Adam, their eyes skittered off me like I’d been Teflon-coated while I was asleep.

Seeing my confusion, Adam said, “It’s because Mom finally told them you were my sister, and they’re all getting used to the idea. They knew there was a control subject in the wild, and I think a few people—like Daisy, maybe—sort of suspected that it was you, but suspecting isn’t the same as knowing, you know?”

Did I ever. “They know I’m really a tapeworm? And who’s Daisy?”

“She works for Mom, and everybody knows.” Adam nodded, seeming to think that this was perfectly normal. For him, it sort of was. SymboGen had dedicated years of therapy and education to making me into a perfect human being; all Dr. Cale had ever forced Adam to learn was how to be a decent person. Maybe those two things weren’t as closely related as I had always automatically assumed. “They don’t care. Or they won’t care, once they get over the shock of meeting the control subject without realizing it. I think some of them are just a little shaky about it, you know?”

“It could’ve been them,” I said quietly. “If one of them had had an implant, and been in that car accident…”

Adam’s head whipped around to stare at me, his eyes wide and somehow affronted, like I had just insulted us both. “It could not!” he said. “Both parts of you had to be strong, and had to be clever in just the right ways, or you could never have become one person. You did it without any help, and that’s more than me or Tansy or even…” He stopped, affronted expression melting into guilt.

“I know about Sherman,” I said, the taste of his name on my tongue setting my stomach roiling again. I was starting to feel numb all the way down to my toes. Too many revelations at once will do that to a girl, I guess. “I get what you’re saying, Adam. I’m just… I’m like the people here, a little. I’m still shaky, too.”

“You be as shaky as you want,” he said. “I’ll be here to help you when you’re done.” He smiled at me.

I smiled back. I couldn’t help it.

We had walked maybe half the length of the bowling alley while we were talking and had stopped just outside a curtain of sliced plastic, cut lengthwise, like the screen on a butterfly aviary or a grocery store produce department’s storage area. I looked at it and swallowed hard. There was something impersonal and medicinal about those dangly strips of waxy plastic, like nothing I was on this side would really matter once I was on that side.

“The broken doors are open,” I murmured.

“That’s my favorite book,” said Adam.

“Of course it’s your favorite book,” I said. Don’t Go Out Alone had been written by a good friend of Dr. Cale. It had been a key part of Nathan’s childhood. It was only natural that it would be a key part of Adam’s as well. I was starting to be a little jealous. I was the only member of our family who hadn’t grown up with that book.

Adam let go of my hand. “If you’re still shaky, I think you’ll feel better talking to Mom and Nathan without me. It’ll be easier to pretend that you’re all humans, and not just all people.”

I wanted to tell him that he was wrong, and that his absence wouldn’t make anything easier at all—that no one ever made anything easier by walking away from it. I couldn’t. When I tried to form the words my lips shaped only silence, and in the end I had to force myself to smile, nod, and say, “I think that might be a good idea. I’ll come find you, though, when we’re done. I think I’m…” I faltered, and then continued, “I think I’m going to need you to teach me a lot of things about the way life is now.”

“Always,” said Adam. Before I could react, he hugged me, let me go, and trotted off into the lab, moving with a lanky sureness that somehow broadcast how comfortable he was in the shape of his own skin.

It seemed indecent, almost: he was a worm wearing a boy like a suit. Shouldn’t he have seemed awkward, or shambled like the sleepwalkers, even? Something—anything—to betray the fact that he wasn’t what he seemed to be. I hadn’t felt that way about him before. I considered the emotion for a moment, spinning it around in my head as I tried to find the angle that would tell me where it was coming from. In the end, though, the answer was so simple that I almost missed it:

Guilt. I hadn’t been guilty when I’d seen Adam before; I hadn’t been allowing myself to understand my own origins, and so I’d assumed I was my body’s original owner. Now I was a stranger in my own skin, and if I couldn’t make myself move awkwardly or look visibly like an intruder—like a thief—I’d think those horrible things at Adam—at my brother.

“No, I won’t,” I ordered myself sternly, and stepped through the plastic sheeting, into the small, white-walled lab beyond.

It was maybe eight feet to a side, creating a space that would have been borderline claustrophobic if that sort of thing had bothered me at all. As it was, it struck me as nicely snug, which meant that it probably made most people uncomfortable. Like the majority of the lab spaces in the bowling alley, this one was isolated only in the most technical sense of the word. The walls didn’t go all the way up to the ceiling, and powerful, if quiet fans were occupied in sucking air up from the floor and spitting it over the top of those three-quarter walls, creating a sort of poor man’s negative pressure zone. It wasn’t quite enough to qualify as a “clean room,” and wouldn’t even have necessarily worked as a quarantine zone back at the shelter, but it was clearly enough for Dr. Cale to feel comfortable setting up some serious hardware. An array of computer towers occupied one wall, their constant buzz setting up a low thrumming sound that vibrated through the soles of my bare feet. Nathan and Dr. Cale were both there already, their attention focused on the same monitor.

“I’m awake,” I announced. They both turned toward me, Nathan with naked relief, Dr. Cale with clinical interest that was so closely akin to the way that Dr. Banks used to look at me that I quailed slightly, shrinking in on myself. “I mean, if it matters. I woke up,” I finished awkwardly.

“How do you feel?” asked Nathan, starting to take a step toward me.

Dr. Cale caught his arm, stopping him before he could fully commit to the motion. “I’m sure we’re both very interested in how Sal is feeling, but we need to finish this, Nathan.” She flashed me a quick, strained smile. “I’m glad to see you up and about. Do you need something to drink? You hit your head pretty hard when you fell, and you’d just given blood. Some orange juice would probably do you a lot of good. Go find Adam, he can take you to get some juice.”

I frowned. “You’re trying to avoid telling me something. You don’t normally try to get me to go away and find juice.”

“Untrue: I gave you juice the very first time you came here,” Dr. Cale replied. “And it’s not like you’ve spent that much time with me. Maybe all of my personal relationships are heavily dependent on juice consumption.”

“You gave me juice that was in the room where we were, and there’s a mini fridge in the corner over there, so if you were that dependent on juice for normal social interaction, you’d be telling me to go and get myself a glass, not telling me to go find Adam.” I folded my arms. “I may not be a human being, but I’m not stupid either. What’s going on? Why do you want me to leave?”

“I told you,” said Nathan, clearly directing his words at Dr. Cale. He was smiling slightly when he turned to face me, although the expression died quickly, replaced by solemnity. Looking at them both, I was struck again by just how much he resembled his mother sometimes. Genetics mattered. “Sal, we’ve been going over the data that you were able to recover from SymboGen. Thank you again for doing that. I didn’t want you to, but I’m coming to understand just how necessary it was.”

I worried my lower lip between my teeth before asking, “How bad?”

“I don’t know. We’ve barely scratched the surface of what’s there—it’s only been a few hours.” He shrugged, his arms flopping limply, like they belonged to a doll and not to a man. “How does the end of the human race sound to you?”

“Oh,” I said, and looked to Dr. Cale. She nodded. That was all it took: one little nod to confirm the end of humanity. “That’s bad,” I said.

-

Chapter 2 SEPTEMBER 2027

The worms being distributed by SymboGen were definitely Dr. Cale’s work: her fingerprints were all over their baseline genetic code, at least according to Nathan, who understood that kind of thing. It looked like a long list of amino acids and DNA chains to me, all of them scrolling by so fast that I wouldn’t have been able to follow them across the screen even if I hadn’t been dyslexic. Still, I had no reason to doubt him when he said that no one but Dr. Cale could have done the core work.

“My original specimens had a very limited amount of human DNA at their disposal, and it was specifically DNA coded to the human immune system,” said Dr. Cale. “It lessened immune response, which made it more likely that the body would view the worm as a friendly guest, and not a hostile interloper. It allowed for a better bond. It was intended to make things… I don’t know. Easier. Better. Between that and toxoplasmosis, there was a very good chance that nothing would be rejected.”

I frowned. “I know all this. Why are you telling me things I already know?”

“Because she doesn’t want to think about the things that you don’t know yet,” said Nathan. “Dr. Banks has been a busy boy.”

“We don’t know that it was Steven,” said Dr. Cale sharply. She turned a glare on Nathan. “The lab protocols at SymboGen have been lax ever since he decided that he’d rather play rock star than stay chained to a desk doing science. There have been a lot of opportunities for unethical people to tamper with our work.”

“And what, Mother? It’s somehow worse if the man who blackmailed you into deserting your family is the one who made the changes to the genome? Is that the piece that finally proves you made the wrong choice? Because I think you of all people should be willing to accept how unethical he is.” Nathan matched her glare for glare before turning his back on her, focusing on me and saying, “The amount of human DNA in the newest generation of worms has more than doubled, and there have been some changes to the toxoplasmosis samples as well, although we haven’t had time to figure out exactly what those changes will mean.”

“It’s worse if this was him, because he knew better,” said Dr. Cale. “Out of everyone in the world, he knew better.”

This felt like the sort of circular conversation that could go on for hours. I interrupted, saying, “We already knew there was human DNA in the tapeworms.”

“Yes, but it was a small enough amount that it should still have been possible to use most common antiparasitics without killing the human host.” Nathan grimaced before continuing, “That’s why you reacted so strongly to the antiparasitics, even though you didn’t die from them. The implants were tailored to break down anthelmintics, to prevent them from being killed by normal medical intervention. If they hadn’t been, the antiparasitics could have…” He trailed off.

“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.”

“That sounds like Sherman,” said Dr. Cale. There was a bleak note in her voice, like she was making light commentary to keep herself from starting to scream. “He used to say that gender was a construct of the body and the mind, and that since his mind was a hermaphroditic worm dreaming of being a gendered biped, he felt no reason to restrict himself any further.”

“But when did he leave here?” I pressed. I vaguely remembered Tansy saying something about him disappearing from the lab six months before I had—before Sally had—before the accident, but I wanted to be sure. So much had happened during my brief visit to SymboGen that I no longer completely trusted my recollections. “Tansy said something about my accident…”

“Yes,” said Dr. Cale wearily. “He left here about six months before Sally Mitchell lost control of her car. I had just finished doing my monthly check on the chimera—”

“The what?” interrupted Nathan.

“Adam, Tansy, and Sherman: my chimera,” said Dr. Cale. “People—and they are people, anything that can think and communicate and tell you what it prefers to be called is a person, regardless of species or origin—who were created by combining multiple organisms. It’s a medical term, usually, for beings that have multiple distinct types of DNA in their bodies. It’s frequently used for people who absorbed their twins while they were in the womb, to give a common example. In mythology, a chimera is a creature made up from bits and pieces of different animals. I use it for the hybrids. It sounds less… judgmental than ‘parasite’ or even ‘symbiont.’”

“So that means me too, now,” I said quietly. Dr. Cale glanced at me, looking almost guilty. I shrugged. “It’s okay. I like it. And you’re right—it’s a better word than ‘hybrid,’ or ‘freak,’ and those were really the only things that I was coming up with. What kind of check were you doing?”

“Making sure there was no tissue rejection or complication, that their human immune systems hadn’t suddenly started attacking their tapeworm bodies as invaders, that there was no mismatch between the neural network and the activity coming from the worm—all fairly standard.” Dr. Cale must have read the dawning disgust in my expression, because she hastened to add, “Dr. Banks was performing very similar tests on you. Chave confirmed it for me, starting when you were brought back to SymboGen for neural mapping. I would have intervened much sooner if I thought that you were in any danger of rejection.”

I wanted to believe her, I really did—I was her tapeworm “daughter,” after all, and I’d been dating her biological son for several years. She had every reason to want to help me stay healthy and psychologically intact. But she wouldn’t meet my eyes, and I had to ask myself whether she’d been viewing me as a true control group: something not to be touched or interfered with, because that would have spoiled her data.

“So Sherman left right after you gave him a clean bill of health,” I said slowly, trying to select the words to make what I was saying both inoffensive and clear. “Did you say anything like ‘this means you’re stable’ or ‘this proves the interface can sustain itself in the long term’ or ‘yay, you’re not going to melt’?”

Dr. Cale frowned. “Maybe…”

Sometimes smart people can be a special kind of stupid. The kind where they know so many facts and are so good at saying “no one would ever do that” that they somehow manage to convince themselves the world is going to care about what they think. It’s like they believe that intelligence alone defines the universe. “So what if he saw that as permission?” I asked. “He left, and he knew what he was, and that humans had created him, and that maybe there was a way to make more like him. And then I happened, and he realized that it could happen naturally. You knew what the signs looked like. So did Dr. Banks. Why wouldn’t Sherman?”

“You think he went to SymboGen specifically to begin engineering the downfall of the human race.” It wasn’t a question, and Dr. Cale didn’t sound horrified when she said it. If anything, she sounded… impressed. Like this was something any parent would absolutely want their son and protégé to think of doing.

I looked to Nathan, too baffled by her tone to know what to say. Thankfully, he wasn’t siding with her on this one. Expression hardening, he looked at her and asked, “Mom, do you think that what Sal is suggesting is possible?”

“Possible, yes,” said Dr. Cale. “Probable, given the rest of what we know… oh, yes. Sherman never went to college, for obvious reasons, but all of my chimera children have helped me in the lab as part of their chores. He understands genetics at least as well as your average lab assistant, and probably better than the majority of them. He knew that we were going to have issues when the human population figured out that their implants had the potential to become sapient; he knew there was a chance that the chimera and human races would wind up competing for ownership of the planet. He could very easily have decided this was the appropriate way to approach the problem, and simply put his plans into action once he managed to find a sympathetic ear.”

“I don’t understand how anyone could think handing their bodies—and their world—over to a different species was a good idea,” I said.

“Humans have done a lot to damage this world, Sal,” said Dr. Cale. “The idea of keeping our human bodies, which are useful things for manipulating the environment, but replacing their brains with something that might be a little kinder…”

I stared at her. “We’re tapeworms,” I said. “We’re parasites.”

“Yes. You don’t kill your hosts on purpose, although you’re more than happy to rewire them to suit your needs. Humans, on the other hand, have a long tradition of killing our hosts. It’s almost a genetic imperative with us.”

“But we kill the original personality,” I protested.

“Biology doesn’t care. The genes are still there; the body is still alive,” said Dr. Cale. “I’m not saying Sherman had the right idea by encouraging his people to increase the amount of human DNA in the implants—if it was Sherman; I’ll be able to tell whether he asked them to use any of my research techniques once I’ve had the chance to cross-check this data against the recent specimens that Tansy brought back from Lafayette—but I am saying I understand how he could have talked other people into going along with him.”

“If this was Sherman, how is he activating the sleepwalkers?” asked Nathan. “What mechanism is he using?”

“I don’t know yet,” said Dr. Cale. “But I will. Trust me on that. I will.”

“My head hurts,” I said, putting one hand against my temple. It felt surprisingly fragile now, like I was carrying around my brain and my body in an eggshell, one that could smash open and spill me on the floor at any moment. “I want to go home.”

Dr. Cale actually looked alarmed. “I’m sorry, but I can’t let you do that.”

“What?” I lowered my hand, staring at her. “What do you mean, you can’t let me do that? I want to go home. Why is that so difficult?”

“Because SymboGen’s security is going to be looking for you by now, and Tansy still isn’t back,” said Dr. Cale. “It’s not safe for you to go out without someone to keep an eye on you. The sleepwalker activity in San Francisco is rather extreme right now.” She shot a meaningful look to Nathan, who frowned and looked away.

I scowled at the both of them. “You didn’t mention my—I mean, Sally’s father, who’s probably looking for me by now, especially if that treatment we suggested for Joyce didn’t work, and did I mention that I don’t care what you think? I want to go home. Beverly and Minnie need to be let out, or they’re going to destroy the apartment.”

“Beverly and Minnie?” asked Dr. Cale blankly.

“Our dogs,” said Nathan. “Sal’s right, Mom. Even if it’s not safe for us to stay in the apartment anymore, we can’t leave the dogs alone there. They’ll run out of food and water, and I’m not willing to do that to them.”

Beverly and Minnie were rescues, casualties of the same epidemic that had claimed so many human lives. Beverly’s owner was last seen in the hospital, sunk deep in the coma that claimed many sleepwalkers in the early stages of their illness. He’d been hospitalized when he lost consciousness, and he’d still been there when vital services began to collapse. I didn’t know whether he had died or woken up and shambled off to join his fellows, but either way, I wasn’t giving back his dog. Minnie’s situation was similarly tragic, and made slightly worse by the fact that Nathan and I had known her owners. Katherine had become sick and had killed her wife, Devi, who used to work with Nathan at San Francisco City Hospital.

Whether she was still trapped in the hospital or loose on the streets of San Francisco, I hoped that Katherine didn’t remember anything about the woman she used to be: I hoped her colonizing worm had wiped her original identity cleanly away. No one should have to live remembering that they murdered their own wife.

I shook my head vigorously. “I didn’t come here to be your prisoner, and I’m not going to stay if I’m not allowed to come and go when I want. I’ve already been through that with the Mitchells. If you’re not willing to let me go and take care of my dogs, I’m going to leave anyway, and I’m not going to come back.”

Dr. Cale sighed, sagging in her chair. “Do you understand that this is all about your well-being?” she asked. “It’s not safe out there, and from what I’ve been able to determine so far from the data you retrieved from SymboGen, it’s not going to get safer anytime soon. Things are going to get much worse before they get better.”

“How much worse?” asked Nathan.

“Ten percent human DNA,” said Dr. Cale grimly. “That’s an apocalypse number.”

“How soon?” asked Nathan.

Dr. Cale hesitated before she said, “I don’t know.”

“Then why don’t we compromise?” I asked. They both turned to me. “Nathan and I will go and get the dogs. We’ll be careful, and we won’t let ourselves get arrested or eaten or anything, but we’ll go, because we have to go. And then we’ll come back here. You won’t keep us prisoner, and we’ll be here willingly for as long as it takes to find an answer that doesn’t end up in the extinction of the human race. But you have to show that you can let us go before we’re going to agree to do that. You have to show that you’re playing fair.”

“I don’t see—” began Dr. Cale.

“Mom,” said Nathan. His voice was soft, but it stopped her dead. She looked at him for a moment, tilting her chin up to compensate for the difference in their heights. Then she sighed.

“I don’t like this,” she said. “You’re my son, and she’s virtually my daughter, in more ways than one, and I don’t like this at all. I’m supposed to keep you safe. It’s my job. How am I supposed to be a good mother to you if you won’t let me do my job?”

“How are you supposed to be a good mother if you’re choosing to be a jailer instead?” asked Nathan.

Dr. Cale didn’t have an answer for that. She just looked away, and said nothing at all.

Half an hour later, Nathan and I were in the front seat of his car, driving toward San Francisco faster than I liked, with strict instructions to turn around and return to the lab if we encountered anything that seemed threatening or out of place. “I can’t lose you,” was what Dr. Cale had said, as she watched us head for the bowling alley door. Adam was nowhere to be seen. I had felt—and still felt—guilty and glad at the same time. I didn’t want him to see me go. Not with Tansy missing, not when there was so much reason for him to question whether I would ever be coming back.

I really hoped we’d be coming back.

Nathan’s attention was fixed almost completely on the road, and my attention was focused on keeping my eyes closed and my shoulders relaxed. If I allowed myself to think too hard about how fast we were going, I would lose my nerve and start screaming for him to slow down, slow down before he got us both killed. It was sort of funny, in an awful kind of way: I existed because Sally Mitchell had suffered a seizure and lost control of her car, freeing the way for me to colonize her brain. But the therapy—or I guess the experiment in psychological conditioning pretending to be therapy—that I’d been required to go through as part of my “recovery” had left me with a phobia of cars and car crashes that bordered on crippling. Had Sally been the one left in our shared body when all was said and done, she would probably have gotten her license back by now. I’d been essentially an infant, and any infant barraged with an unending stream of automotive horror stories would have developed a phobia just like mine.

Thinking about that made it even harder not to be angry with Dr. Cale, and with SymboGen, for the way they’d allowed me to be handled. I wasn’t a control group. I wasn’t an experiment. I was a person, and they shouldn’t have psychologically damaged me just to see what would happen if they did. Dr. Cale knew what I was from the moment I opened my eyes. She shouldn’t have allowed me to be twisted into something that I was never going to be.

She shouldn’t have let them try so hard to turn me into a human.

“We’re approaching the end of the bridge, Sal,” said Nathan, using the light, almost aggressively conversational tone he always affected when he was trying to keep me from panicking during a stressful car ride. I was grateful for that consideration, even as I resented it. My boyfriend shouldn’t have been forced to speak to me like I was a child because someone else had taken it upon themselves to give me a phobia I didn’t need to have.

The resentment helped a little. It enabled me to focus as I forced myself to nod, keeping my eyes closed. The car was curving slightly to the left, navigating the bend in the exit from the freeway. We’d be on city streets soon. That would mean more traffic, more drivers to work around, but no big blue ocean underneath us; no threat of sinking to the bottom of the Bay and being lost forever if we took one wrong turn. The change would help. The change always helped.

Then I heard the sirens up ahead. That was all the warning I got before the car came screeching to a halt, the tires squealing against the surface of the road. The seat belt drew suddenly tight, the momentum of the car throwing me forward before flinging me hard back into the seat again. I shrieked, a high, panicky sound that seemed to steal all the air from my lungs. The drums were suddenly loud, not just beating in my ears, but pounding, thudding until they drowned out the world. I sank down into them, letting the sound wash over me until it felt like the panic was starting to leach away, dissolving into the sound and the thin red screen that suddenly blurred my vision, turning everything carmine and bloody-bright.

There was a hand on my shoulder. I didn’t want to think about it. Thinking about it would have meant admitting that I had a shoulder, and that it existed in a physical place where people could reach out and take hold of it. It would mean letting the world back in. I wasn’t ready for that. Panic had its claws in me, and there wasn’t room in the world for anything else.

“—please, Sal, you need to snap out of it. Please.” Nathan gave my shoulder another shake, digging his fingers in harder this time, until I had no choice but to acknowledge his reality. “I’m sorry, I’m so sorry, but I can’t wait. You have to open your eyes. Please.”

I took a breath, the red scrim over my vision receding slightly. As it did, it was replaced by blackness, and I realized that my eyes were still closed. Once I realized that, it was hard but not impossible to force my eyes to open. First a crack—barely a sliver, barely enough to let the light come flooding in—and then all the way, blinking against the glare, the world resolving into a blurry photograph, splashes of color on a black and white background. I blinked again. The color came back. The blurs became people…

… and the people were sleepwalkers. An ocean of sleepwalkers, hundreds of bodies thronging in the streets of San Francisco. They hadn’t reached the bridge yet, but they were close; the exit was clogged with them, some shambling by almost close enough for me to roll down my window and touch. The sirens came from the police vehicles and fire trucks that blocked the intersection just off the bridge, their lights flashing and their doors standing open as the rescue personnel tried to do their jobs against impossible odds. They were trying to rescue the people. The people were no longer really present anymore.

I stared at the crowd, trying to find individuals among the weaving bodies. Age, race, gender, socioeconomic background—none of it mattered now that their implants were in control. A little girl shambled past, her mouth hanging slack, a runnel of drool charting a path down her chin to dangle above her chest. I put a hand over my mouth. These were early-stage sleepwalkers, nonviolent, confused but not attacking anyone. That was a good sign. It wasn’t going to last. Not with this many sleepwalkers in one area, and not with the tapeworm brains in the process of building fast, flawed connections to the human minds that they were trying to control. Eventually, higher thought and human instinct would both give out, and tapeworm instincts would take over.

Tapeworm instincts only really came with one command. These people were going to start looking for food, and any unturned or unimplanted humans still in the area were going to be prime targets.

Unimplanted humans meant Nathan, who had never been given an Intestinal Bodyguard. “We have to get out of here,” I said tightly. The sleepwalkers couldn’t possibly hear me through the closed windows, especially not with the sirens going off so close by, but I still felt the urge to whisper. “They’re going to notice us soon. We need to drive.”

“They’re everywhere,” Nathan said, his voice pitched equally low. “Where do you want me to go?”

“I don’t know. Anywhere. Nathan, they’re mobbing. Once they figure out what’s going on, they’re going to turn hungry.”

“Or they’re going to go to sleep. That’s what most of the ones at the hospital did.” He sounded hopeful.

“Only with the ones you found alone. Have any of the mobs stayed calm or gone to sleep of their own accord?”

Nathan hesitated before shaking his head. “No,” he said. “No, that hasn’t happened. But we don’t have that big of a sample set. We’re still finding different forms of interaction. It depends on the strain of D. symbogenesis that’s set up shop inside each of those people’s brains. Some of them are peaceful. Some of them aren’t.”

“Is there anything that could tell us what strain they’re infected with?”

“No.”

“Then drive.” I actually reached out and shook the wheel with one hand, ignoring the thin jet of panic it sent snaking through my belly. “We need to get the dogs, and we need to get out of this city. If it’s already this bad…”

“Sal, you’re not going to like what I have to do.”

“I know.” I pulled my hand off the wheel, closing my eyes as I shrank back down into my seat. “If I start screaming, just ignore it. Get us home.” I closed my eyes.

“I love you,” said Nathan, and he hit the gas, weaving around the milling bodies as he aimed for the gap in the barricade. He was trying not to hit them. He almost succeeded, although we clipped a few as we passed. I felt bad about that. Not bad enough to ask him to stop. Some of the police yelled and waved their arms, but most of them were too busy with the sleepwalkers to pay attention to the commuters who were just trying to get away. Things were falling apart.

If the screech of tires when the car stopped had seemed loud, the squeal of tires against the pavement as we accelerated was louder than anything else in the universe: louder than the sirens, louder than the drums, even louder than my pained screams. I clapped my hands over my eyes, turning the wash of red inside my eyelids into solid black. Nathan drove, and I screamed. That was how it had to be.

Nathan’s first turn took us hard to the right, toward Market Street. He picked up speed as we drove, until I had no idea how fast we were going or how many turns he had taken. I bent forward, resting my forehead on my knees, and screamed until my throat was raw as sandpaper. It hurt, and I tried to focus on the pain as I continued to scream, choosing that over the frantic, irregular movements of the car. We were going to crash at any moment, I just knew it, and when that happened, we were going to die. We were both going to die.

At least this time, it’s going to be your accident, I thought, a thin line of rationality drawing itself across the black and red landscape of my fear. It wasn’t as reassuring a thought as I had wanted it to be.

“Almost there, honey!” shouted Nathan. The words barely penetrated the fog.

San Francisco is a smaller city than it seems from the outside, miles and miles of streets packed into a relatively narrow stretch of land. It’s possible to walk there for hours without ever seeing its borders. At the same time, if someone knows the territory, knows what they’re doing, and doesn’t mind violating a few traffic laws, it’s possible to drive across the city in less than twenty minutes.

If there was a traffic law that Nathan didn’t break in those twenty minutes, I didn’t know about it, and my terror wouldn’t allow me to open my eyes long enough to find out. The car screeched to a halt, the engine cutting off, only to be replaced by sudden silence. The drums were still pounding in my ears, but the screams had stopped. It took me several seconds to realize that it was because I had stopped screaming.

Cautiously, I removed my hands from my face and opened my eyes, looking around. We were parked behind Nathan’s—behind our apartment building, catty-corner across two spaces in a way that was guaranteed to alienate our neighbors.

“Can you move?” asked Nathan.

I nodded wordlessly.

“Good. Then let’s move.” He opened his door and jumped out of the car before slamming it closed behind him, moving with an urgency that I wasn’t used to seeing from my usually staid, scholarly boyfriend.

My back was a solid knot of tension as I forced myself to sit up, undo my seat belt, and open the car door. I started to stand, only to fall to the ground as my knees refused to bear my weight, sending me sprawling. Nathan ran toward me.

“Sal! Are you all right?”

“I’m fine.” I grasped his offered hand, using it to pull myself back to my feet. My palms and knees were stinging. Gravel had cut through my skin, leaving the heels of my hands red and raw. I laughed a little, wincing at the faint edge of hysteria in the sound. “Let’s remember to grab the first aid kit, okay?”

“Okay,” said Nathan, keeping hold of my hand as he kicked the passenger-side door shut and started toward the building entrance.

I let him lead, and focused on listening as hard as I could to our environment, looking for any sign that we were not alone. I could hear cars driving by, and the distant sound of sirens—but that didn’t necessarily mean anything. We were far enough away from the bridge exit that I couldn’t be hearing those sirens, and San Francisco is a city with a lot of sirens. Police cars, private security, ambulances, they all made up the constant background noise of the city. I was probably just hearing one of those, and not a sign that the crisis was getting worse in our immediate vicinity.

A thin line of ice curled and uncurled in my belly, almost like a new kind of parasite. You don’t really believe that, murmured that little inner voice, and it was right. I knew the situation was devolving around us, and we didn’t have very long. Maybe pressuring Dr. Cale into letting us go home had been the wrong thing to do… but we couldn’t leave the dogs. They needed us, and unless the world was burning, that wasn’t a trust that I was willing to break.

There were no moans on the thin, smoke-scented air. Even if the mob of sleepwalkers was spreading, it either wasn’t here yet, or it wasn’t attacking yet. We had a little bit of time.

Nathan got the door unlocked and tugged me inside. I let go of his hand and took the lead down the hallway to the stairs. We didn’t even discuss using the elevator. The mob by the bridge had drawn the fragility of our situation into sharp relief, and the last thing that either of us wanted was to be trapped between floors if the electricity suddenly cut out.

The stairwell was silent save for the soft clicks of our shoes against the steps, and the sound of Nathan’s faintly labored breathing after the third floor. Neither of us was in the best of shape, but at least my tendency to walk when I couldn’t get a bus somewhere meant that I did all right with things like “walking up eight flights of stairs.” By the time we reached our floor, his face had taken on a distressingly plummy cast, and he wasn’t talking anymore, just nodding when I looked back and asked if he was all right. I paused on the landing, my hand on the door handle, and waited for him to catch up.

“I don’t think we should go through until you catch your breath,” I said. “We don’t know what’s up there.” Nathan’s building had a limited number of apartments per floor, and most were occupied by single residents or couples, rather than entire families. I wasn’t certain how many people we shared the floor with, but I knew that it was less than ten. That was a good thing, because most of them were also young urban professionals, the kind of people who thought that no price was too high to pay for the opportunity to avoid needing to take a sick day. The kind of people the SymboGen implant had been virtually designed for. If they had started their cascade into sleepwalker-dom…

We would cross that bridge when we came to it. “My life made a lot more sense a week ago,” I said, almost contemplatively.

Nathan looked at me, his hands braced on his knees and his black hair lank with sweat. It hung into his eyes, making him look disheveled. “I don’t think either of us has had a life that made sense in years,” he said. “We’ve just started noticing how strange everything is.”

“The broken doors are open,” I said sourly.

“Come and enter and be home,” Nathan replied. “Open the door, Sal. I’m okay to keep moving.”

I wanted to argue with him. I wanted to tell him that we needed to take a few more minutes so that he could catch his breath and I could prepare myself for whatever was waiting in the hall. And I knew how much I hated it when people argued with me about my own assessment of my mental or physical state, so I didn’t say anything. I just nodded, once, and opened the door.

The man standing on the other side was almost an anticlimax. He was barefoot, and his pants were unfastened, like he had been in the process of getting dressed when his thoughts became scrambled and unclear. His mouth hung slack, although he wasn’t drooling. There was no one behind him: the hallway was empty and beckoning, promising safety and lockable doors, if we could just get past the poor soul who was staring blankly at us.

“Hi,” I said. It wasn’t a good start. I couldn’t think of anything else to do.

The man twitched. Not a lot—I wouldn’t even have noticed it in someone like Nathan or Dr. Cale, who still moved like the living, all heat and suddenness—but enough that it was clear he was responding to my voice. His eyes refocused on my face, vague interest sparking in their depths. My breath caught, my lungs seeming to constrict like collapsing balloons. He knew I was there. He could hear me.

“Sal…” said Nathan. His voice was low, marbled with amazement and fear. Amazement because this man knew I was speaking to him somehow: fear because we both knew what the sleepwalkers could do.

“I mean, hello,” I said, eyes still on the sleepwalker. His ability to respond at all was incredible. Maybe he was a chimera, like me: maybe this was how the conversion process began in someone who was actually awake and not sunk deep into a trauma-induced coma. At any moment, his eyes might clear, and he might become a confused, amnesiac person who needed to be guided through his new life. The human who had owned this body was already gone, and I knew abstractly that I should be mourning for him—he hadn’t done anything wrong, not really, apart from trusting a company that could afford to buy hundreds of hours of advertising time that said their products were safe. But he was gone, and if one of my cousins was here now, I should take care of the living.

Even more abstractly, I knew that I wouldn’t have been able to remain this calm if Nathan had been at risk—if Nathan had possessed a SymboGen implant, I would have been moving heaven and earth to get it out of him as quickly as possible. But this wasn’t Nathan. This was a stranger, and whoever he had been before was already gone.

The sleepwalker continued to look at me, an almost puzzled expression in his glazed blue eyes. He moved his mouth silently, and the first gob of spit escaped, running unfettered down his chin.

“I’m Sal,” I said, pressing a hand flat against my chest. “This is Nathan. We’re not going to hurt you. We’d like to help you, if you’d be willing to let us—” I reached my hand out toward him, not coming close enough to startle, but hopefully close enough that he would be able to recognize my offer of support as what it was.

The sleepwalker’s mouth moved again, like he was struggling to remember how to form words. Then, in a low voice that was only barely above a moan, he said, “Saaaaaaaaal.”

I blanched, starting to pull my hand away. That was when the sleepwalker moved.

Like many of the sleepwalkers we’d encountered, he was fast: something about the flawed interface between tapeworm thought and human mind had removed the normal limitations imposed by the body. He didn’t know that he needed to be afraid of hurting himself. He just moved, lunging with an inhuman speed as he latched his hands around my wrist. I screamed, trying to pull away. It was an automatic response, offered without thought for the sleepwalkers that might be lurking in the other apartments on the floor, and it was louder than I would have believed possible, given the torn-up state of my throat. The sleepwalker clamped down harder. He wasn’t just fast, he was strong, and I could feel the bones in my wrist grind together.

“Sal!” Nathan grabbed my other arm. Just in time, too: the sleepwalker gave a mighty tug and I stumbled forward, barely held in place by Nathan’s frantic grip.

“Let me go!” I shouted, trying again to jerk myself free.

“Saaaaaaaaaaal,” responded the sleepwalker, and pulled my arm toward his mouth.

The feeling of his teeth breaking the skin of my wrist was like nothing I had ever felt before or wanted to feel again: intensely painful, and almost unreal at the same time. This couldn’t be happening. This couldn’t be happening. It didn’t make sense, and so my brain tried to reject the reality of it, shoving it aside in favor of the pounding sound of drums rising in my ears. Nathan pulled on me again, and for a moment, it was like I was being torn in two. My shoulders ached. The sleepwalker’s teeth dug deeper into my wrist. I screamed.

Nathan let me go.

I whipped around as best I could to stare at him, too stunned to keep screaming. The sleepwalker yanked me closer, his teeth digging into my flesh until it felt like they were scraping against the bone, and then Nathan was squeezing past us both and running down the hall, one hand fumbling in his pants pocket.

I realized what he was doing as he shoved the key into the lock, and I shoved my hand against the sleepwalker’s face, trying to break his hold on my wrist. I didn’t expect it to work. It didn’t really need to. It just needed to distract him a little bit, to keep him focused on me while Nathan got the door open.

The dogs must have been waiting just inside for us to return. Nathan kicked the door inward, and Beverly’s long, low growl echoed out into the hall, followed by the sleek black shape of Beverly herself rocketing for the sleepwalker’s knees. Beverly was a black Lab that we had acquired when her original owner went into conversion; it had been her barking and growling that alerted us to the fact that something was wrong with him. Most animals hated sleepwalkers. Something about the chemical changes to the body that occurred during an invasive takeover upset them. Beverly took that hate to a new level.

The man who was trying to gnaw through my wrist might not have known much about pain anymore, but that didn’t make him immune to the laws of physics. Beverly slammed into his knees and he let me go, moaning in confusion as he struggled to keep his balance. The gash in my wrist was almost three inches long. Thanks to the way his teeth had broken through skin and muscle, the wound ran up and not across. Beverly was growling, and Minnie was barking from somewhere inside the apartment, and I was bleeding everywhere. So much blood.

The sight of it actually helped a little. It meant I was on a time limit. I danced backward, getting away from him, and waved my arms in the air, trying to keep his attention on me rather than allowing it to switch to my dog. He staggered forward, arms outstretched, a moan bubbling from his lips.

“I’m sorry,” I said, and grabbed him by the hair, yanking with all of my might. The motion made the open wound in my wrist burn with new pain. But Beverly was still hitting him from behind, and with me pulling from the front, I was able to navigate him to the head of the stairs. He moaned again. I swiveled, and shoved.

The sound of his body rolling down the steps from the eighth floor to the seventh, and then down to the sixth, was like a sack of oatmeal being dropped. Something snapped when he was about halfway down, and the moaning stopped. I stayed where I was, panting and panicked, my wrist bleeding copiously, and stared after him, waiting for some sign of movement. None came.

Beverly stepped up next to me, leaning against my leg as she whined and tried to shove her head into my hand. “It’s okay, Bevvie,” I said, patting her automatically. It caused more pain, but not much; shock was starting to slide between me and my injury, blurring and soothing its edges. Blood loss was probably also helping. “You’re a good dog. You did good to hurt that bad man. Good girl, Bevvie, good girl.”

Then Nathan was there, putting his hands on my shoulders and pulling me inexorably away from the stairs. “Come on, Sal,” he said. “I need to get a bandage on that before you lose too much more blood.”

I nodded mutely, and went with him, leaving the body of the sleepwalker—the person I could have been, had things gone just a little differently during Sally’s accident—behind us.

-

The worst part is that I know everyone blames me, and they’re not wrong.

There was a time when it was easy to make choices and say that history would vindicate my genius. I was standing in the present, and when you’re only thinking about today, history is always so far away. You have a lot of time to kill before history comes knocking and demands you live up to all those big claims you made. History is the ultimate thesis review board, and unlike the board that reviewed my thesis, history doesn’t take bribes.

I always swore that I was going to do great things with my life, things that would change the world in a way that could never be undone. Well, I guess I got my wish. I brought an end to the Age of Mankind.

Good for me.

–FROM CAN OF WORMS: THE AUTOBIOGRAPHY OF SHANTI CALE, PHD. AS YET UNPUBLISHED.

Chapter 3 SEPTEMBER 2027

The dogs were as upset over the blood and screaming as I was. Minnie met us just inside the apartment, looking like she was on the verge of a canine panic attack—there was a certain brightness to her eyes and unsteadiness to her normally rollicking bulldog gait that I didn’t like at all. Both our dogs had lost their original owners to the sleepwalking sickness. But while Beverly had chosen to run away from her former master when his implant took him over, Minnie had tried to stay with her owners, and she had still lost them both. For her, this situation had to verge on the nightmarish, and there was no way to make her understand what was really going on.

Then again, there was no real way to make me understand it, either. The science was all gibberish delivered by people wearing white coats and serious expressions; the fact that I was actually a tapeworm in a woman-suit made no more or less sense than anything else that had happened in my short, improbable life.

“God, Sal, you’re bleeding everywhere.” Nathan let go of my wrist long enough to push Beverly fully inside before he turned and locked the door. Then he steered me to the kitchen table, looking back over his shoulder several times as he checked my face for signs that I was still with him. “I’m so sorry, I didn’t… I just didn’t expect to see him there. That was Mr. Bouman from Apartment 8C, down the hall. He must have found a way to open his door after he converted, and then forgotten it by the time he got to the end of the hall…”

I tried to muster a response, but my fear that it would come out as a wordless moan kept me from saying anything. The world was starting to go black and fuzzy around the edges, swarmed by countless tiny dots of nothingness. It was like insects were eating away at the borders of my vision, and I was helpless to do anything but let them. I didn’t like that. I scowled at the insects. The insects, which didn’t technically exist, ignored me.

I knew when we had reached the table less because I was paying any attention to my surroundings, and more because Nathan placed his hand on my shoulder and pushed me down into a chair. I didn’t fight him. Gravity was a simple thing, and it seemed better to just let it do what it wanted with me.

“Sal, I need you to keep pressure on this.” His voice echoed.

I blinked at him, and then at my wrist, which had somehow been wrapped in a dish towel that was rapidly turning bright red with my blood. He was pressing down hard enough that it should have hurt, and probably would when I took a moment to breathe.

“Come on, sweetie. I know it hurts, but I need you to stay with me here. I need you to keep the pressure on while I get the first aid kit.” Nathan took my free hand in his and pressed it down on the sodden dressing. I did my best to mimic his motion, pushing down until there was an unpleasant squishing sensation, things shifting under my fingers that had nothing to do with the towel.

Nathan, at least, looked somewhat relieved by my response. That made one of us.

“Stay here; I’ll be right back,” he said, and then he was gone, disappearing into the depths of the apartment and leaving me alone to try to fight against my body’s natural desire to bleed to death. Minnie and Beverly stayed with me, their furry bodies plopped down to either side of my chair and their enormous brown eyes fixed on me, like they thought they could just wish everything better.

“Should’ve designed dog,” I mumbled, my fully coherent thought—that the Intestinal Bodyguard should have been designed for dogs, which would be much easier things to be than humans—turning into so much gibberish by the time it finished making the journey to my mouth. I sighed and sagged in place, finally allowing my eyes to slide closed. The drums were there, in the silence behind my eyelids, although they were neither as strong nor as steady as they usually were. That was probably a bad thing. Then again, what wasn’t a bad thing, anymore?

I must have blacked out. That shouldn’t have been much of a surprise, considering the combination of shock and blood loss that I was dealing with, but I was still surprised when I opened my eyes and found myself staring up at the living room ceiling, with a pillow supporting my head. I tried to sit up. A wave of dizziness assured me that this was a terrible idea, and that I should stay where I was for as long as possible. Maybe forever.

I groaned.

“Oh, good, you’re awake,” said Nathan. He paused. “Are you awake? If you’re not awake, just don’t respond. But I’d really prefer it if you were awake.”

I licked my lips, which were somehow dry and gummy at the same time. “How long was I out?” I managed to croak, and felt ridiculously proud of myself for accomplishing that much. Everything was still a little gray around the edges, but it was no longer in danger of being swallowed up by shadows, and I thought that was probably a good sign.

“Two hours,” said Nathan. I heard him get up. His footsteps moved away, followed by the sound of the fridge door opening and closing. Then the steps returned, moving toward me with purpose. “I’ve been monitoring your vital signs. Your pulse has remained mostly steady, though you should have gone to the hospital, given how much blood I’m guessing you lost.”

“No hospitals,” I whispered, alarmed.

“No, no hospitals,” Nathan agreed. He sat down on the edge of the couch, setting something on the coffee table. There was a smudge of blood on his chin, and his hair was even more disheveled, making him look younger and lost. “It was killing me not to take you there, but given what we’ve seen so far today, I think it would have killed us both if I’d tried getting you to the ER. Not to mention the danger that the police would get involved.”

Possibly forcing him to choose between leaving me there and getting arrested, depending on what story SymboGen was spinning about the break-in and theft of their data. I grimaced. “Thank you.”

“No thanks needed. We’re in this together.” He kissed my forehead tenderly before asking, “Do you think you can sit up if I help you? I want you to drink some juice.”

“I think so.” I took his arm, making note of the clean white dressing on my wrist as I did so, and allowed him to half help, half pull me into a seated position. The room swam briefly out of focus, and then swam back just as quickly. “Oh, wow. Oh, ow.”

“Are you dizzy?”

“A little bit,” I said, starting to nod. I realized at the last moment that it would be a bad idea, and turned the motion into a semi-bob of my chin instead. Even that was enough to make my head spin. “Everything’s a little gray around the outside.”

“As long as it’s just gray and not black, you should be okay.” He picked up a glass of orange juice from the coffee table, offering it to me. “This will help.”

“I’ve given enough blood voluntarily to know that orange juice doesn’t equal instant recovery,” I said, and took the glass. My hand was shaking. I willed it to be still, and once I was sure I wouldn’t spill juice all over the floor, I raised the glass to my lips. Sweetness flooded my mouth, almost strong enough to make me gag. I did choke a little, before forcing myself to keep on drinking.

“The better it tastes, the more you need it,” said Nathan. He grimaced wryly, and added, “Except when it goes too far, and you feel like you’re turning into a hummingbird. And no, orange juice isn’t an instant restorative. But you didn’t lose enough blood to need a transfusion, thank God, or we would have needed to go to the hospital no matter how bad an idea that was. This should give you enough of a boost that we can get back to the car with the dogs.”

“Thank you for not being willing to let me die in our kitchen,” I said, and took another drink of orange juice. “Has anyone noticed the body in the stairwell?”

“Not that I’ve heard. The building’s been pretty quiet since you passed out. As for the rest of the city…” Nathan shook his head. “I turned the news off when I realized that it was just getting worse. We’ve passed some sort of critical mass of sleepwalkers. More and more of the implants are waking up.”

I looked at him solemnly as I sipped the juice, trying to force myself to choke every last drop of it down. There was no way any of this was a coincidence; not with Sherman on the loose, not with his team of doctors dedicated to championing the cause of D. symbogenesis over the cause of the human race.

I was almost relieved to realize that the thought that he was doing this on purpose made me sick to my stomach. I might not be human, but I still knew right from wrong. That was no small accomplishment, given the circumstances.

“Sal? What’s wrong?”

“I don’t think it was just reaching a critical mass that triggered this,” I said, setting the empty juice glass back on the coffee table. Nathan was right about one thing: while I still felt shaky and weak, I no longer felt like I was going to collapse back into unconsciousness at any moment. “This is Sherman. He was so mad, Nathan. I think he really expected me to go with him. To just throw up my hands and say, ‘I understand now, I’m really one of you,’ and let him lead me to his secret lair beneath the city.”

“If his secret lair is under San Francisco, the first big earthquake will solve this problem for us,” said Nathan. There was a brittle edge to his voice, like he was joking because he didn’t know what else to do. “Do you really think Sherman could do this?”

“I think Sherman doesn’t consider himself human, and he doesn’t see dead humans as dead people,” I said. “He was pretty clear on that point when we were at SymboGen. He wants to be the dominant species. He wants us to be the only things that live here. And we know that sleepwalkers trigger other sleepwalkers. If you wanted to spread them through the city like… like a real disease, all you’d need is a few index cases to scatter around the streets. They’d go wandering and anyone they encountered who was on the verge of going over would succumb.” It was so simple, so elegant, and so horrible that I could barely believe that Sherman, who had always been kind to me, could possibly be behind it.

But then, I’d thought we were both human in those days, and he’d been playing along with my assumptions, hadn’t he? It was easy to pretend to follow social rules when you didn’t really believe that they applied to you.

“God.” Nathan got up again. This time the dogs followed him into the kitchen. He returned with the bottle of orange juice, refilling my glass before he set the bottle down on the table. He also had a package of Fig Newtons, which he held out to me. “Eat as many of these as you think you can stomach. If you’re right, and Sherman is doing this, we need to get the hell out of this city.”

“He doesn’t know where we live,” I protested, taking the cookies.

“No. But USAMRIID knows that there’s an outbreak in San Francisco, and they don’t know yet exactly how the sleepwalking sickness is being spread. They don’t know that lockdown is already a lost cause. If they decide to quarantine the city…”

I blanched. My father—Sally Mitchell’s father—was a career army man. He had reached the rank of colonel before he retired from active duty and took over the local branch of USAMRIID, the United States Army Medical Research Institute of Infectious Diseases. The last time I’d seen him, he’d been releasing me from his custody in exchange for a possible cure for his daughter, Joyce. His only surviving daughter, I realized with a pang. She wasn’t really my sister. Somehow that was worse than knowing that he wasn’t really my father. Unlike Joyce, he had always held himself a little bit apart from me, and now I knew the reason why: he had known all along that Sally was dead, and he had been monitoring me to see how the tapeworm in my driver’s seat reacted. He’d turned his little girl’s corpse into a science project for his country.

The only real family I was ever going to have was the one in Dr. Cale’s lab. We had to get Tansy back.

“We have to get out of here,” I said, before pulling open the package of cookies and cramming two of them into my mouth, effectively ending my part in the conversation while I chewed and swallowed.

“Yes,” said Nathan, looking relieved. “We’ll need to take the elevator down—I don’t think we can deal with both dogs and our suitcases on the stairs. Not with your wrist and a dead body in the way.”

“What if the power goes out?”

His expression turned grim. “Let’s just not think about that, okay? You eat. I’m going to finish packing.”

I wanted to argue with him, to point out that being trapped in an elevator during a major outbreak would be a stupid, pointless, horror movie way to die. I didn’t say anything, because he was right. He couldn’t handle going up and down the stairs repeatedly, and that’s what he’d have to do if we wanted to get the two dogs and their things to the car. Adding our possessions—and while I didn’t have many, I had to admit to being somewhat attached to the ones I did have—to the mix took things to a whole other level. We needed that elevator. And we needed one hell of a lucky break.

Nathan vanished into the bedroom while I sat on the couch inhaling cookies. Beverly and Minnie stayed with me, their liquid brown eyes hopefully tracking every little motion that I made. They knew a sucker when they saw one. I gave each of them a cookie and took advantage of their distraction to shove three more into my mouth, nearly choking myself in the process. I washed down the sticky mass with a long drink of orange juice. The resulting combination wasn’t the worst thing I’d ever put into my mouth, but it certainly wasn’t among the best.

I was trying to cover the taste with the last of the Fig Newtons when Nathan emerged from the bedroom. He had a suitcase in one hand, and was dragging my roller bag with the other. He walked over and deposited them both next to the coffee table before saying, “One second,” and darting back into the bedroom.

This time when he emerged, he was carrying the small plastic terrarium that we used to transport plants between home and his office. About half of our shared collection of sundews, pitcher plants, and Venus flytraps was crammed inside, their root systems dangerously overcrowded by what had clearly been a very hasty transplant.

“I hate to leave the others, but this was the best I could do,” said Nathan, pushing his glasses nervously up the bridge of his nose as he walked over and set the terrarium down next to my orange juice. “I grabbed some of your clothes, basic toiletries, and your journals. Was there anything else you wanted me to bring? I’m afraid we don’t have much room, but we could probably get a few more things into the suitcases if we really shoved.”

“No, nothing,” I said, and stood. My legs were still a little wobbly, but I was reasonably sure that they would support my weight. “Get the leashes, and then let’s get out of here.”

Nathan smiled. “I love you.”

“I love you, too,” I said. He tossed me Minnie’s leash, correctly assessing my condition as “up to the bulldog, not quite ready for the Lab.” Beverly stood up, tail wagging and attention fixed on him. She was clearly aware of whose leash that was, and what it meant for probable walkies. “Do we have anything remotely like a weapon?”

“Just the carving knives from the kitchen,” said Nathan. He bent to clip the leash to Beverly’s collar. “And the dogs, I suppose. Our friend from the hall clearly learned that a dog can be a weapon.”

“I’ll get the knives,” I said, and turned.

Walking to the kitchen served a dual purpose: it let me get the carving knives from the butcher’s block next to the microwave, and it also let me assess my ability to walk in a straight line without hurting myself. My head spun a little, but that was it; apart from that, and a general all-over weakness, I seemed to be mostly okay.

Nathan had made an effort to wipe down the kitchen table, but there had been other things on his mind, and he’d missed more than a few streaky patches of my blood, now dried to a dark reddish brown that looked almost like coffee stains against the wood. I stopped to look at it for a few seconds, waiting for my throat to tighten and my stomach to clench. It didn’t happen. This was my blood; it had been created to keep me alive while it was inside me, and it did a very good job. Now that it was outside of my body, it didn’t really matter anymore. I was almost relieved to realize that my opinion about that sort of thing hadn’t changed now that I was in mortal danger, instead of just being marginally confused by the world around me.

“Sal?”

“Coming!” I gathered both knives, careful to hold them away from myself, and walked back to the living room with Minnie at my heels.

Nathan had the terrarium balanced atop my roller bag, held in place with a bungee cord. He was holding Beverly’s leash in one hand and his suitcase in the other. He put the suitcase down long enough to take the knife I offered him. “All right,” he said. “As soon as I open the door, run for the elevator. If anyone tries to attack you or stop you from getting there, do whatever it takes to get them out of your way.” He paused, looking startled by the words that were coming out of his mouth. “Oh, God. Is this my life now? ‘Do whatever it takes,’ and planning attacks on the elevator call button?”

“The key word there is ‘life,’” I said, tucking the remaining knife into my belt before bending to clip Minnie’s leash on. She wagged her stubby tail and panted at me, clearly overjoyed by the prospect of going for a walk, no matter how strange the circumstances surrounding it happened to be. “This is your life now, because this is a life that lasts long enough for us to get back to your mother’s place. We can disappear with her. We’ll be safe until this blows over.”

Nathan frowned. “Sal… do you honestly think this is something that’s going to ‘blow over’?”

I didn’t have an answer.

The hallway was empty when Nathan and I cautiously peeked our heads out of the apartment door, the dogs straining at their leashes and eager to be on their way. It was a struggle to keep my grasp on Minnie’s lead, making me even more grateful that Nathan was able to handle Beverly. I at least stood a chance of restraining Minnie if she decided to go for a sleepwalker. With Beverly… there would have been no chance, and things would have ended poorly for everyone involved.

The power hadn’t flickered once. I was choosing to take that as a good sign, and kept reminding myself that it was a good sign as I half ran, half stumbled down the hall, hampered by both my overall bodily weakness and the suitcase-slash-terrarium construct that I was dragging behind me. We’d abandon our things at the first sign of trouble—nothing either one of us owned was worth our lives, except for maybe the dogs, and we’d already risked death to save them—but if we were going to be at Dr. Cale’s for a while, we were going to want a few familiar things around us.

The idea of going into hiding in someone else’s secret lair made the drums pound harder in my ears. I had only recently escaped from the house of Sally’s parents, who had been determined to keep me penned up like a child rather than admitting that I had grown up to be someone other than their daughter—although maybe that was all Sally’s mother speaking. Her father had his own reasons for keeping me captive, and they had nothing to do with the pretense that I was Sally Mitchell. Motives didn’t change the fact that I’d been a prisoner for my entire life, and now I was willingly going into a new kind of cage. I guess that in the end, the urge to survive is stronger than almost anything else.

Nathan pressed the elevator call button. We stood there nervously, our shoulders touching, as if physical proximity could provide us with some measure of protection. The panel above the elevator dinged comfortingly, marking the approach of our way out. I was starting to think that everything was going to be okay…

And Beverly was starting to growl.

It was soft at first, almost subsonic when it caught my attention. I looked down at her. She had her ears pressed flat against her skull, giving her an angular, predatory cast, and her lips were drawn back, showing the pale lines of her gums around the white, dangerous angles of her teeth.

“Nathan?”

He didn’t turn, his eyes intent on the light of the elevator call button.

I looked toward Minnie. She was growling too, deeper and lower than Beverly—so deep and low that I had mistaken the sound for the rumble of the approaching elevator. She and Beverly were facing the same way, down the hall, toward the other apartments.

“Nathan,” I said again, a little more loudly—but not much, no, not much. I was starting to think that making noise was the last thing that either of us wanted to do. “I think we’re about to have company.”

“What?” He followed my gaze to the end of the hall, and then looked down at the wild-eyed, growling dogs, who had taken on that stiff-legged posture characteristic of canines defending humans since the dawn of time. He paled. “Oh. Fuck.”

“I think we may have to take the stairs.”

“I don’t know if we can get there,” he said slowly. “One of those doors is between us and them.”

“Oh.” Things had seemed almost hopeful only a few seconds before, even if “hope” had been redefined on the local level to mean “slightly less bleak.” Now, with an unknown number of sleepwalkers approaching, it was difficult to muster anything but resigned despair. “I don’t know what to do, Nathan. None of my remedial education classes covered how to escape in the middle of a zombie apocalypse.”

Nathan laughed once, a single short, sharp bark that actually distracted Minnie from her growling long enough to give him a quizzical look. “Surviving the zombie apocalypse was an incredibly popular topic of discussion with the folks I went to college with. Too bad no one ever came up with a simple solution for ‘zombie apocalypse, genetically engineered parasite variant.’ I’d be the savior of the human race if they had.”

I was opening my mouth to answer him when the first moan drifted around the corner at the end of the hall, followed by another, and another, until it sounded like an entire mob was shambling our way. At least none of them was saying my name—not yet, anyway. Whatever half-decayed connection allowed the sleepwalkers to recognize me as a chimera was present, but no one had given them a word to hang on what I was. Not that awareness of our relationship would keep them from attacking me. As the man in the stairwell had proven, they could recognize me and still want to rip my throat out with their teeth.

“Nathan…”

“I know.”

We both backed up until we were pressed against the closed elevator doors, holding to the dogs’ leashes for dear life. I could deal with the fact that I was probably about to die. The fact that I was still weak from blood loss meant that I would almost certainly die first, saving me from needing to see what my tapeworm cousins would do to Nathan. But I couldn’t bear the thought of seeing the dogs ripped to pieces by the sleepwalkers. The dogs could do a lot of damage before they were killed. The sleepwalkers barely acknowledged pain. They would win.

“You know, in all my wildest dreams, this was never how I imagined I would die,” said Nathan. He sounded almost wistful. “I mean, I assumed you would be there, but that it would either be one of those ‘dying in bed at the ripe old age of a hundred and twenty, my beloved wife by my side’ situations, or a freak surfing accident while we were on our honeymoon.”

“You surf?” I paused. “Wait, honeymoon?”

“I surf,” he confirmed. “And yes, honeymoon. I mean, assuming you said yes when I finally got up the nerve to propose.”

“If we get out of here alive, you should try it,” I said.

Nathan smiled sadly, and said nothing.

The first of the sleepwalkers shambled into view, moving toward us with slow, implacable purpose. The dogs were still growling, but louder now, like they still thought that they could somehow dissuade these unwanted intruders on their space through volume alone. My insistence on grabbing the knives suddenly seemed like a child’s demand for a security blanket. We were two people with kitchen cutlery and no training, and I was already injured. All we could do with those knives was slit our own wrists and hope that we bled out fully before the sleepwalkers ripped us apart.

“I’m really glad I got to know you,” I said.

“Me, too,” said Nathan. “Marry me?”

The elevator doors opened.

We were pressed flat against them, and when the support suddenly left our backs, we toppled over, taking suitcases, terrarium, and dogs with us as we tumbled into the elevator. Luck was with us for the first time since we’d left the lab: there was no one already inside, waiting to take a bite out of our tender flesh. I squeaked shrilly, surprised and disoriented. Nathan scrambled to his feet, slamming the heel of his hand down on the door-close button. I managed to sit up just in time to see the blank, emotionless faces of the sleepwalkers blocked out by the closing elevator doors.

Beverly and Minnie stopped growling, their belligerence transforming instantly into confusion. Minnie sat down, beginning to scratch her ear with her hind leg. I picked myself up from the floor, pausing to right the luggage and make sure I hadn’t dropped anything. My heart was hammering in my chest so hard that it hurt, and for once it didn’t sound like drums at all—it sounded like the heartbeat of a mammal, panicked beyond reason and confronting its own mortality.

Nathan was standing squarely in the middle of the elevator by the time I finished getting to my feet. His carving knife was in his hand, and his shoulders were shaking, betraying the depth of his distress. It was weird to realize that of the two of us, I was probably the one handling things better. Then again, I was also the one who was accustomed to the world being turned on its head. Nathan liked his routines. He was used to things being just so, and even dating me hadn’t changed that. My chaos hadn’t intruded on his daily life—not until recently, anyway.

“Nathan?” I kept my voice low, like I was speaking to a panicky animal. In a way, maybe I was. My still-pounding heart was doing its best to remind me that humans were just animals, as subject to the whims and whimsies of biology. The fight or flight response was wreaking havoc with both of us.

I’d always wondered why I sometimes passed out before I really panicked, despite everyone I knew working almost exactly the opposite. If “I” was a separate beast from the brain that stored my memories and emotional response, though, it started to make sense. Too much adrenaline flooded the mind, and I got knocked out of the synaptic loop, resulting in a loss of consciousness but not total loss of cool. Inefficient. Doubtless unintentional, too. So much about my design was.

“We don’t know what the lobby’s going to look like.” Nathan’s voice was soft, uninflected—virtually dead. If I hadn’t known that he’d never been fitted with an implant, I would have rethought my position on panic when I heard him speak. “If there are sleepwalkers there, if it’s dangerous, take the dogs and run. I’ll hold them off so that you can get away.”

“And go where? Nathan, I can’t drive. I never learned, and even if I had, I’d never be able to make myself drive away and leave you. We could run off down the street, but if the situation is that bad, we’d just be eaten by the next swarm of sleepwalkers we saw. We’re staying with you. We’re staying together. That’s the only way that we’re going to get out of this. Together.” I forced myself to smile. “Besides, you know your mother would kill me if I called her from the Concord BART Station and said, ‘Hey, I left your son to die but I made it to the train, do you think you could come and pick me up?’”

Nathan chuckled.

The floor indicator counted down from three to two.

My hands were full, and I didn’t dare let go of anything I had. Nathan had already dropped his suitcase, and the mere fact that he would prioritize my dog—our dog—over the only personal possessions he had been able to save made me even more certain that marrying him was the right course of action. He didn’t care that I was a tapeworm in a human skin, but he cared about proper leash etiquette. I was never going to find a more perfect man.

“I love you.”

“I love you, too.”

The counter reached one with a soft “ding,” and the elevator doors opened to reveal an anticlimactically empty lobby. I blinked, unable to believe what my eyes were seeing. Only Minnie tugging on the leash as she eagerly tried to pull me out of the elevator to the walkies she assumed were waiting for her snapped me out of my fugue.

“Run,” said Nathan, stuffing the knife back into his waistband and grabbing his previously discarded suitcase.

We ran.

The street outside the apartment building was eerily deserted, as if all of San Francisco had suddenly realized they had better things to do than their afternoon commute. Two people, both bloody, running with suitcases and dogs out of a private building and into an equally private parking lot, should have attracted some attention of the police persuasion. We saw no one, and if anyone saw us, they didn’t bother contacting the authorities—or maybe they did, and the systems had already reached the point of overload. That was a question that would never be answered, because there wasn’t time to stop and ask, and there were more important things for us to do. Like escaping the prison that San Francisco was about to become.

We threw our suitcases into the trunk, placing the terrarium with only slightly more care, and loaded the excited, overstimulated dogs into the backseat before getting into the front. Nathan waited for me to buckle myself in before he hit the gas, but only barely. For once, my phobias were going to have to take second place on the list of priorities, and even as I swallowed the rising tide of panic—and the rising bile in my throat—I agreed with this decision. I could have hysterics when we got out of this.

The drums were back in my ears, pounding steadily and reassuringly. I wondered what my tendency to freak out in cars meant for my “Sal passes out before the chemicals can make her panic” theory, and decided that since this particular strain of panic was psychological, not triggered by physiological reactions, it ran according to a different set of rules, even though the actual biochemistry probably wasn’t all that different. This question kept me occupied for almost six blocks, which made it worth the contemplation. Anything to distract me from the way that Nathan was driving.

Then I glanced up, and frowned as I recognized the neighborhood around us. “Nathan, where are you going? This isn’t the way to the Bay Bridge.”

“That’s because we’re taking another route,” he said. “There were too many sleepwalkers there, and that was hours ago. By now the area has either completely devolved into chaos, or the authorities have it locked down. We’d be lucky if they let us onto the bridge at all. If we were particularly unlucky, they’d take one look at us and haul us off for medical testing. I don’t know about you, but I didn’t escape from that apartment building just so I could go into quarantine.”

“I don’t want that either,” I assured him. “So where are we going?”

“Down the coast to the San Mateo Bridge. It’s going to be a longer drive, and I’m really sorry about that. I should be able to slow down once we’re past the airport.”

I forced myself to nod as if I was okay with this plan, as if it didn’t make me want to fling myself screaming from the car. “I may try to sleep, if that’s all right with you. I don’t know if I can, but it would give me something else to focus on.”

The corner of Nathan’s mouth that I could see twisted downward in obvious displeasure. “If you really need to, okay. Just, I may wake you up if your breathing seems shallow, all right? I don’t know how much blood you lost back there, but between that and the shocks you’ve had today, I want to keep an eye on you.”

“All right,” I agreed, and closed my eyes.

The San Francisco Bay Area sounds like it should be small, cozy even, the sort of place you can see in a day if you really enjoy spending time in a car. But just like San Francisco itself is deceptively small, the Bay Area is deceptively large. It’s too big for any one transit system, bridge, or highway to accommodate, and the only way someone could see the whole thing in a single day would be to start at midnight and never stop the car. Twenty-four hours might be enough time to drive through all the major cities, as long as you were quick and not overly concerned with actually seeing anything.

My car issues and reliance on buses and BART trains meant I was mostly familiar with San Francisco proper, and some parts of the East Bay—the ones with good farmer’s markets or interesting local attractions, like Solano Avenue and their annual street fair, or the big animal shelter out in Oakland. Caltrain ran between San Francisco and the South Bay, but since I’d never had a pressing reason to spend time down there, I really didn’t know much about the geography beyond “every time they try to put in a BART extension, San Jose comes up with another way to block it.” I got the feeling the residents of Silicon Valley didn’t like being lumped into the San Francisco family of cities, and the feeling was pretty much mutual.

Most California biotech had started in Silicon Valley, eschewing San Francisco’s high rents and prohibitive restrictions on keeping livestock. But money, as they say, talks, and the biotech industry didn’t want to spend forever in the shadow of the computer revolution. Bit by bit the big firms had oozed their way into the seaside communities, setting up shop in Santa Cruz, Monterey, and yes, San Francisco, home of SymboGen, the biggest biotech monster of them all. Dr. Banks had tried to explain the reasoning to me a few times, focusing on the substantial hydroelectric potential of the Pacific Ocean, as well as the availability of marine biomass. He’d dodged my questions about overfishing and conservation, responding to them with one of those warm, paternal smiles that always sent shivers running up and down my spine.

“Besides, Sally, an ocean view says you’ve got the money to afford it, and that makes investors feel better about opening their wallets for you. The more money we have, the better the care we’ll be able to provide—now, and for the rest of your life. It’s a win-win situation, don’t you think?”

Those had been his exact words. As I sank down into the darkness behind my eyelids, trying to focus on the drums pounding in my ears, I wondered what he was saying now. Did he still think the ocean view was worth it when it came with geographic isolation and possible captivity in a city that was about to become a living hell?

I didn’t know, and there was no way for me to ask him.

The drums were erratic at first—soothing, but irregular, thanks to my lingering upset over Nathan’s driving. They smoothed out as I sank deeper into my own mind, retreating down into the hot warm dark that was the first thing I remembered. My old therapist, Dr. Morrison, used to tell me that the hot warm dark was a representation of the womb, a result of my damaged psyche trying to regress to a time when it experienced absolute safety. He’d been very, very wrong, but he’d been right in a way, too, because he’d been claiming that I was trying to go back to a simpler time, and well…

I was pretty sure the hot warm dark was my only real memory of my time before I joined with Sally Mitchell’s unused brain. A time when all I needed to do was eat, and occasionally shift positions in her digestive system, aligning my spreading flower of a mouth with another rich source of the nutrients I needed to survive. I wouldn’t have gone back to that state of being for anything—sapience is addictive—but it had been good while it lasted, hadn’t it? All my memories of the hot warm dark told me it had been. It made so much more sense now.

San Francisco was fading into memory and shadow behind us, surrendered to the sleepwalkers and the grasp of the coming crisis. I didn’t know if we were ever going to go back to our lives; I didn’t know how bad things were going to get. Being inhuman didn’t give me the ability to see what was coming. Too bad. We could have really used a little foresight right about then. We needed to stop Sherman. It was too late to save the sleepwalkers, but maybe Nathan and Dr. Cale could find a way to make the implants stop waking up, or at least stop them from accidentally hurting their hosts. Maybe we could figure out how to make that information public without bringing USAMRIID and SymboGen down on our heads, and maybe we could save the rest of the people, both human and chimera, who still needed saving.

It was a lot of “maybe,” but I wasn’t done yet. I thought of Tansy. My sister. Maybe she’d managed to fight off the sleepwalkers and hide somewhere, injured but alive. Maybe she’d come home, make a joke about zombie brains, and ask me to go sledding. Maybe…

“Maybe” was becoming addictive. I was so tired. I breathed in, letting the embrace of the hot warm dark draw me further down, and Nathan drove on, carrying us into the uncertain future.