The last of the crackers went to Elise. I broke the sleeve in half out of habit, remembered there was nothing left to divide it from, and pressed the whole thing into her palm. She was crouched against the guardrail of the overpass with her knees pulled up, nine days of grime on a face that used to take forty minutes to do every morning. "You have to eat something too, Mara." "I ate." I hadn't since Tuesday. I wasn't sure which Tuesday. Daniel stood a few steps up the ramp, holding the binoculars he'd taken from a sporting goods store before the whole block went dark. He didn't turn around. He hadn't turned around much since the second night. "Ridge road is clear," he said. "Two miles. Aldercrest is right behind it." "You keep saying that name like it's a promise." "It is one." He finally looked at me, and his face did what it always did, softened at the edges, made me feel like the only person in a very large room. Eleven months of that face across a dinner table. A ring in my pocket I'd stopped wearing on day three because it caught on things. "My firm poured the foundation. I've got the code. Nobody else knows it's there, Mara. Nobody." I believed him. That is the part I would like to scrape out of myself, if I could. I believed him the way I'd believed everything for twenty-six years, completely and without checking. Below us, the city made a sound I'd stopped being able to describe. It wasn't screaming anymore. Screaming needs breath and people had run out of it. It was a low, wet shuffling, thousands of feet on broken glass, and under it something that sounded almost like humming. Elise lifted her head. "They're closer." They were. A column of them was coming up the off-ramp from the river district, and I had been a nurse long enough to know the stages by their gait. The fevered ones stumbled. The turned ones walked. These walked, all of them, in a line so straight it looked drawn with a ruler. At the front was a woman in a gray hospital cardigan. I knew the cardigan before I knew the face. Mrs. Abernathy, bed 12, a retired schoolteacher who had made me promise every night to check that her cat was fed. Her cat had been dead for eleven days. She had been dead for at least four. She walked past Daniel. Within arm's reach, close enough to brush his sleeve. He flinched and she didn't even turn her head. She walked past Elise, who curled into the guardrail with her hands over her mouth, and Mrs. Abernathy stepped around her like a fence post. Her eyes were fixed on me. "Mara," she said. It came out of her like a recording played backwards, but it was my name. I should have run. Instead I stood there with a tire iron in one hand and my last good thought in the other, which was: why me? Then the man behind her lunged for Elise, and I stopped thinking and swung. I don't remember the next minute in order. I remember the sound the iron made. I remember Elise's scream going up an octave. I remember Daniel hauling her to her feet by the arm, saying "Go, go, go," and the three of us tearing up the ridge road with the entire column turning behind us like a school of fish changing direction. Turning toward me. Not them. Me. We ran until my lungs felt like torn paper. The road climbed through dead pines and abandoned cars, and my sister's hand slipped out of mine twice, and twice I went back. Both times I told myself it was because she was younger, because I'd raised her from fourteen, because our mother would have wanted it. The truth was simpler. Going back for people was just what I did. It was the only thing I knew how to be. Aldercrest was not a building. It was a hillside with a door in it. Gray steel, taller than a bus, set into a poured concrete lip. A keypad glowed green beside it, impossibly alive in a dead world. Daniel hit the code with fingers I noticed were shaking, and something deep in the mountain groaned, and the door began to roll sideways on a track as wide as a train rail. Warm air came out. Clean air. It smelled like carpet and machine oil, like a place where someone had planned for you. Elise went through first. Daniel went after her, one hand on the small of her back, and I stayed on the threshold with my pack because someone had to look behind us. The ridge road was full. I counted forty, and then I stopped counting. They were coming up through the pines at a steady, patient walk, hundreds of paces back. Mrs. Abernathy was still in front. They didn't hurry. They didn't need to. They knew exactly where I was going. "Mara." Daniel's voice, from inside. "Come on." I turned and took one step across the track. The door stopped. Not a stutter, not a jam. It stopped the way a held breath stops. I looked up and Elise was standing at a red lever set into the wall, a hand-crank override, painted the color of an exit sign. Her palm was flat against it. Her face was wet. "Elise." She wouldn't look at me. She looked at the floor between us, at the line of steel where the door would meet the wall, as if the line was the only thing in the world she could stand to see. "Elise, it's me. It's me." "I know," my sister said. She pulled the lever down. The door started to move. Not the slow glide it had opened with. It slammed, a hammer-fall of pneumatics and servos, and I threw my shoulder into the gap and caught a sliver of light and sound and air. Daniel was standing twelve feet back with his hands open at his sides. That is what I think about. Not Elise. Daniel, with his hands open, like a man who has just set something down. He didn't shout. He didn't reach for the lever or for me. His mouth moved, and I have gone over it a thousand times, and I think it was: I'm sorry. Not "stop." Not "wait." Sorry. The gap closed on my fingers and I pulled them free, leaving skin on the steel. I hit the door with both fists. I screamed their names. I screamed my sister's name until it stopped sounding like a name. The metal was cold and perfectly smooth and it did not even ring. Behind me the humming had become a chorus, and the shuffling had become a rhythm, and I turned around with my back flat against the only thing in the world that was supposed to save me. They stopped ten feet away. Mrs. Abernathy was in front, her cardigan buttoned wrong. They all stopped, hundreds of them, in a half circle on the concrete, and they looked at me with a terrible stillness, the way you look at a person you have walked a very long way to reach. Then something happened I did not expect. Someone was shouting. "MARA!" A man was fighting up the ridge road through the back of the crowd. He had a fire axe and a torn paramedic's jacket and blood to the elbows, and he was swinging with a ferocity that would have made me afraid of him on any other day. He was cutting a path straight toward me. He was shouting my name like it was the only word he had left. I didn't know him. I remember thinking that clearly. I didn't know him at all, and he was killing people to get to me. He didn't make it. The first of them reached me before he was halfway. Mrs. Abernathy put both hands on my face, very gently, almost tenderly, and the rest followed. I slid down the door and felt it against my spine, steel and cold and sealed, and I thought: this is the last thing I will ever lean on. But it wasn't cold anymore. The door was humming. Through my back, through my ribs, through the dying edges of me, a low steady vibration like a machine waking up. And underneath it, a sound that I had never heard come from a door in my life. Slow and mechanical and patient. It sounded like a clock being wound.

I died with my cheek against steel, and I woke up with my cheek against a pillowcase that smelled like lavender detergent. For a long moment I did not move at all. I lay on my side with my eyes open, watching a strip of morning sun crawl across a wall I knew, painted a blue I had argued over for an entire weekend. Somewhere below the window a garbage truck ground its gears. A bird, ridiculous and cheerful, said the same three notes over and over. No humming, no hundreds of feet. My hands were the first thing I checked, because hands were what I had left on the door. I lifted them in front of my face. Ten fingers, nails chipped from the pharmacy shelves but whole. Palms clean. The skin I had torn off on that gap of steel was just skin again, unmarked, pink, ordinary. Nursing training takes over before grief does. That's the one useful thing it ever gave me. I pressed two fingers to my own neck and counted against the clock on the nightstand. One hundred and forty beats a minute. Pupils likely dilated. Oriented to place, because I knew exactly where I was. Oriented to time, because I did not. "Hey." A hand settled between my shoulder blades. Warm, broad, familiar. "Mar. You're shaking. Bad dream?" Daniel. I have thought about what I should have done in that second, and the honest answer is that there was nothing to do. My body made the decision for me. Every muscle I owned locked at once, and I held myself so still that he felt it, because his hand paused, a quarter inch off my spine. The man who had stood twelve feet back with his palms open was rubbing my back and asking if I'd had a bad dream. "Yeah," I said. My voice came out scraped raw. "Bad one." "You were talking in your sleep." He propped himself up on an elbow, hair flattened on one side, the sheet creased across his chest. Alive, rested, nine days of grime gone from his face. He looked at me with a faint worried crease between his eyebrows, exactly the way he'd looked at me the night my father's old watch broke. "You kept saying her name. Elise. Over and over." "I was just worried about her." "Of course you were." He kissed my temple. The kiss was real. That was the worst part, and I would spend a long time learning how to hold it. It was a real kiss from a man who loved me. "You're freezing, babe. Stay in bed. I'll start coffee." He left and I listened to his bare feet on the floorboards, the squeak of the third step, the kitchen tap running. Then I grabbed my phone off the charger and stopped breathing. Monday, It was eleven minutes past seven in the morning. I knew that date. I had stared at it, at the digital clock in a pharmacy a week and a half into the end of the world, because the pharmacy's calendar had still been turned to the right month and I couldn't stop thinking about how normal it looked. The sky came down on the twenty-third. The alert, the first screaming broadcast, the day everyone remembered. Twenty-one days. I sat on the edge of the bed and put my head between my knees and breathed through my mouth until the room stopped tilting. The phone slid onto the rug. I did not pick it up. I was twenty-six, again. I had been twenty-six and ten months when I died, and I was twenty-six and ten months now, and the only thing that had changed was that somewhere behind my ribs there was a record of a world that did not exist yet. Slowly, like pulling a splinter, I thought: they don't know. Daniel didn't know. Whatever he had decided in the dark, whatever arithmetic he had done to be able to stand there with his hands open, it hadn't happened yet. As far as he was concerned, I was the woman he was going to marry, and I'd had a nightmare about my sister. I stood, my legs held. I went to the bathroom, locked the door, turned on the tap so the water would cover the noise, and put a towel over my mouth, and screamed into it until my throat tasted of metal. When I came out, I washed my face. In the mirror, I looked terrible and also unmistakably young. No hollows under my cheekbones. No cut on my lip from a fall on the ridge road. I stared at myself until I recognized something in the eyes, a flatness that had not been there the last time I'd looked at this particular reflection. Then I put on a sweatshirt and went to find my sister. The kitchen smelled like syrup and burnt butter but I heard her before I saw her. She was humming, off key, a song from a commercial. Elise stood at the stove in Daniel's oversized college sweatshirt with her damp hair twisted up in a clip, flipping a pancake with the focus of a surgeon. Her face was bare and clean and smooth. Her fingernails were painted a chipped coral. Her shoulders had the loose, easy line of someone who had slept eight hours in a bed. She turned around and saw me, and she smiled. I have tried since to describe that smile accurately, because I know it was the key to everything. It was not forced. It was not cruel. It was open, bright, and a little sheepish, the face of a twenty-four-year-old who knew she'd burned the first batch and wanted me to forgive her before I saw. It was the smile I had worked for. Fourteen years of double shifts and skipped meals, and her braces, and her prom dress, and every scholarship form I'd ever signed with my own tired hand. "Morning, sleepyhead," Elise said. "You look awful." "Thanks." "No, I mean it nicely." She crossed the kitchen and wrapped her arms around me, chin on my shoulder, the familiar weight of her against my back. Those hands, resting over my collarbones. Those exact hands. They had flipped a lever on a wall. I didn't scream. I don't know how I didn't. I stood there inside the circle of my sister's arms and let her squeeze me and felt something terrible happen in my chest. It wasn't hatred. I wished it had been hatred. Hatred would have been clean. It was love, still there, still warm and stupid and fully functional, like a limb that doesn't know it's been cut off. "You're crying," Elise said, pulling back. "Bad dream." "Aw, Mar." She swiped her thumb under my eye. "It was just a dream." "Yeah." I nodded. I made myself smile. "I'm sure it was." Behind her, on the counter, Daniel's phone buzzed against the granite. He was at the coffee machine with his back to us, humming along with Elise now, the two of them off key in perfect, practiced harmony. The screen lit up where it lay, face up between the fruit bowl and a pile of mail. I was close enough to read it. Marcus, Hale Group: Ridge site passed final inspection. Mr. Hale wants the full structural team on site Friday for the door test. Bring your code. The preview cut off there. Daniel turned, saw me looking, and swept the phone into his pocket with an easy, careless motion. "Work stuff. Boring." "Sounds important." "Not really." He crossed the kitchen and slid a mug into my hands, hot, chipped, the one with the faded lighthouse. "Eat something, Mar. You're too pale." I took the mug. I looked at my sister, flushed and glowing at the stove. I looked at the man I had been going to marry, smiling at me over the rim of his own cup. The sun came through the window above the sink and lit the whole room gold, and the syrup was warm, and nobody in that kitchen had any idea what I was. They were both smiling at me. Neither of them knew I had already died at their door. I lifted the coffee to my lips so I wouldn't have to say anything. That was when I heard it, so faintly I almost mistook it for the refrigerator. A slow, patient mechanical tick, rising up from somewhere beneath the floor, beneath the building, beneath the whole waking city. I glanced at the wall clock above the stove. Its hands were moving, silent as a held breath. Whatever I was hearing, it wasn't coming from there.

By nine o'clock the apartment was empty, and I had not decided yet whether that was a relief or a mistake. Daniel left first. He kissed me at the door with his laptop bag over one shoulder and said he'd try to be home by six. Elise left ten minutes later, borrowing my umbrella without asking, the way she had borrowed everything of mine since she was eleven. "Love you!" she called from the stairwell, already halfway down. "Love you too," I said to the closed door. It came out easily. That frightened me more than anything else that morning. I stood in the hallway until the building went quiet. Then I went back to the kitchen, washed the three plates, wiped the syrup off the counter, and sat down at the table with a pen and the pad of paper that lived beside the grocery magnets. I'd been a nurse for four years. When the world fell apart, I wrote it down. That was the only method I had. I wrote the date at the top. Then I stared at it for a long time. The trouble was that I did not trust my own head. A mind that has died once does not feel like a mind that is working properly. It felt like a house after a flood, everything still standing, but the floors soft, the walls remembering water. I could see the ridge road. I could see Mrs. Abernathy's buttoned cardigan. What I could not do, I discovered, was put the events in a straight line. So I started with the things I was sure of. The alert came on the twenty-third. I'd watched it in a break room with six other nurses, a government voice reading a statement that kept getting interrupted by a second, quieter voice off camera. Nobody said the word infection. Somebody said containment, and Priya from pediatrics dropped her coffee. The first blackout came after that. I wrote it down, and then stopped with the pen on the paper. The sixth? The seventh? I had held that date in my hands for nine days. I had counted toward it. I had stood in a stairwell in total darkness and thought, this is the sixth night, the sixth, and it was gone. Not erased, exactly. Just out of reach, the way a word goes when you try too hard to say it. I could feel the shape of the answer, and nothing inside it. I wrote both numbers down with a question mark. My hand was steady. My stomach was not. It's fine, I told myself. It's been less than two hours. You've been awake less than two hours. I moved on to the smaller things, the details that don't matter to anyone but the person who lived through them. A cold front that would hit the city tomorrow night. A transit strike announced on Wednesday, called off on Thursday. The name of a pop star who would be hospitalized on the nineteenth, which sounded insane written down, but I'd heard it in the break room the day before the alert and it had been the last thing anyone talked about that was not the end of the world. None of it was useful. All of it was a test. I picked up my phone, still lying where I'd dropped it on the rug, and opened the weather. A cold front, arriving tomorrow night. Temperatures dropping eleven degrees by Wednesday morning. I put the phone down very carefully, like something that might go off. Then I got dressed, because if I sat in that kitchen another hour with my own handwriting I would start to come apart. I put on jeans and my gray coat and walked to the corner store on the next block, not because I needed anything, but because I needed to be near other people who did not know. The man behind the counter was reading a newspaper. An actual paper, folded in quarters, a habit I'd always found charming. I bought a pack of gum and a coffee and stood by the door while I flipped through it. Page three. A transit workers' union threatening to walk out on Wednesday. I read it twice. My eyes kept sliding off the words and landing on the paper's masthead, the date, the little weather icon in the corner. I stood there until the man looked up and asked if I was all right. "Fine," I said. "Sorry. Long night." "Aren't they all," he said, and went back to his paper. I walked home the long way. Past the bakery, where a girl in a striped apron was chalking the day's specials on a sandwich board. Past the bus stop, where three people waited and one of them was laughing into a phone. Past the pharmacy, my pharmacy, the one with the calendar on the wall. Its windows were bright and clean. Somebody had taped a paper snowflake to the glass. I stopped in front of it for longer than made sense. This was where I had stood on day eleven with a tire iron, looking at that same calendar through a smashed door. Same sign. Same chipped green awning. In nine days this window would be gone. A woman came out with a paper bag, glanced at me, and slowed. "You okay, hon?" I opened my mouth to say yes. What came out instead was a laugh, a small, ugly, wet thing. I put my hand over my face. "Sorry. I'm sorry. I'm okay." "No, I know that look." She laid a hand on my arm, light, brief. "Bad week? Mine too. Get yourself something warm. It helps, I swear." She walked away. I stood there with my coffee going cold and my eyes burning, understanding that she was the first stranger who had touched me in this life. In the last one, the last person who had done that was Mrs. Abernathy. I made myself walk the rest of the way home. Back at the table, I turned to a fresh page. At the top, in block capitals, I wrote: WHAT CHANGED. Underneath it, nothing. A single line, and then a second. It was a joke. It was a notebook about differences, and I had nothing to compare yet. Everything I did from here on, every purchase, every phone call, every word I said to the people I loved would nudge this world a little off the track I remembered. I wanted a record of exactly how far. Below that I wrote three rules. One. Tell no one. Not Elise, not Daniel, not anyone. Two. Write down everything that happens, the day it happens. Three. Do not trust a date. I looked at the third rule for a while. Then I added, under it, smaller: Not even mine. The apartment ticked and settled around me. Refrigerator, radiator, the floorboards cooling. I held very still and listened for the other sound, the slow patient one from under the floor. I sat for five minutes, Ten, still nothing. Just an ordinary old building doing its ordinary old noises. I should have felt better but I didn't. There was one more thing to do, and I had been putting it off since the kitchen. I reached into the pocket of my coat, then my jeans, then the zippered pouch of my bag, and then I remembered it was in the small dish on the dresser where it always lived when I showered. I went to the bedroom and picked it up. A thin gold band with a small stone. It had been in my pocket for eight days of the end of the world, and I had stopped wearing it because it caught on things. I turned it over in my fingers. It was warm from the sunlight on the dresser. Daniel had gotten down on one knee in the middle of a restaurant that smelled like garlic and cried, actually cried, and I had said yes before he'd finished the question. He had meant it. I believed that. I believed it with the same part of me that still believed in the lavender detergent and the bird outside the window, the part that had not been told. If I was going to be lied to by two people who loved me, I could at least be the first one who started. I slid the ring onto my finger. It fit exactly as it always had. Then I picked up my phone and texted my sister, because the Mara who died at that door would have, and the Mara who woke up was going to need to keep being her for a while. Dinner at mine tonight? I'll make that pasta you like. The three dots appeared almost at once. Then, a second later: YES. Daniel says he has news, btw. Something about work!! Don't tell him I told you. I read it three times. I put the phone face down on the dresser and stood in the middle of my bedroom, in the pale ordinary light, with my own handwriting waiting in the kitchen. Then I went to buy groceries for the last family dinner I would ever cook without knowing what I was feeding.