“You can do it, Elias,” I murmur to him with each flight, hoping he can hear me but knowing he’s probably so deeply lost in fever that my words are meaningless. But I say them anyway because they comfort me and keep me focused.

When I finally get him to our flat I spread a few blankets on the floor and roll him onto them. He retches again but his stomach’s empty and nothing comes up. As carefully as possible I peel the frozen clothes from his body, his skin now a chilly pale blue.

He pulls himself into a ball, shivering, and I pile more blankets on top of him and drag him closer to the stove. For now he seems content to let sleep draw him under and I toss wood on the fire and then just stand there, staring at my sister and Elias, wondering what to do next.

Wondering how I’m going to keep them alive.

There’s always been sickness in the City. Several years ago a flu raged through, decimating the population. I’d been one of the afflicted and Elias traded almost everything he had—food credits, blankets, his nice boots, oil and a lantern—for the herbs to bring down my fever. He later told me he sat by my bed for a week, his hand against my chest when he slept to make sure I kept breathing.

I look at his body now, at the way his cheekbones angle under the skin. My sister’s the same way, skin wan and hair lank. I wonder how either of them can be strong enough to survive this kind of fever for a week.

I let myself fall into a chair and sit, counting the number of times their chests rise and fall. I watch their eyelids flutter and lips mumble words that never become clear. The moaning of the horde swims through the window, wrapping around us all—calling to me.

All I can think is, What happens if I can’t save them? What if it’s just me in this building alone until I can’t survive any longer? Of all the ways I imagined the world would end, this was not one of them.

I lean over, tucking my forehead into my knees, and cover my ears with my hands. I can no longer hold back the tears and I cry, letting the fear shake through me.

I spend the day waiting for Catcher and trying to coax Elias and my sister to drink slushy snow, trying to feed them broth they can’t stomach. A few times they wake up but when I talk to them, they don’t seem to recognize me.

My sister cries out for her mother, moaning the name Mary, and all I can do is hold her hand and tell her it will be okay even though I’m not sure it will be.