We walk in silence, although the rat-man occasionally stops, making clicking motions with his tongue, like a man calling a dog. Once he crouches, and pulls bits of crushed crackers from the pockets of his coat, scattering them on the ground between the wooden slats of the tracks. From the corners of the tunnel the rats emerge, sniffing his fingers, fighting over the crumbs, hopping up into his cupped palms and running up over his arms and shoulders. It is terrible to watch, but I can’t look away.

“How long have you been here?” Julian asks, after the ratman has straightened up again. Now all around us we hear the chittering of tiny teeth and nails, and the flashlight lights up quick-moving, writhing shadows. I have a sudden terror that the rats are all around me, even on the ceilings.

“Don’t know,” the rat-man says. “Lost count.”

Unlike the other people who have made their home on the platform, he has no noticeable physical deformities except for his single milk-white eye. I can’t help but blurt out, “Why?”

He turns abruptly back to me. For a minute Rat-man doesn’t say anything, and the three of us stand there in the stifling dark. My breath is coming quickly, rasping in my throat.

“I didn’t want to be cured,” he says at last, and the words are so normal—a vocabulary from my world, a debate from above—that relief breaks in my chest. He’s not crazy after all.

“Why not?” That’s Julian.

Another pause. “I was already sick,” the rat-man says, and although I can’t see his face, I can hear that he is smiling just a little bit. I wonder if Julian is as surprised as I am.

It occurs to me, then, that people themselves are full of tunnels: winding, dark spaces and caverns; impossible to know all the places inside of them. Impossible even to imagine.

“What happened?” Julian persists.

“She was cured,” the rat-man says shortly, and turns his back to us, resuming the walk. “And I chose … this. Here.”

“Wait, wait.” Julian tugs me along—we have to jog a little to catch up. “I don’t understand. You were infected together, and then she was cured?”

“Yes.”

“And you chose this instead?” Julian shakes his head. “You must have seen… I mean, it would have taken away the pain.” There’s a question in Julian’s words, and I know then that he is struggling, still clinging to his old beliefs, the ideas that have comforted him for so long.

“I didn’t see.” The rat-man has increased his pace. He must have the tunnel’s twists and dips memorized. Julian and I can barely keep up. “I didn’t see her at all after that.”

“I don’t understand,” Julian says, and for a second my heart aches for him. He is my age, but there is so much he doesn’t know.

The rat-man stops. He doesn’t look at us, but I see his shoulders rise and fall: an inaudible sigh. “They’d already taken her from me once,” he says quietly. “I didn’t want to lose her again.”

I have the urge to lay my hand on his shoulder and say, I understand. But the words seem stupid. We can never understand. We can only try, fumbling our way through the tunneled places, reaching for light.

But then he says, “We’re here,” and steps to the side, so the flashlight’s beam falls on a rusted metal ladder; and before I can think of anything else to say, he has hopped onto its lowest rung and started climbing toward the surface.

Soon the rat-man is fiddling with a metal cover in the ceiling. As he slides it open, the light is so dazzling and unexpected I cry out for a second, and have to turn away, blinking, while spots of color revolve in my vision.

The rat-man heaves himself up and out through the hole, then reaches down to help me. Julian follows last.

We’ve emerged onto a large, open-air platform. There is a train track below us, torn up, a thicket of mangled iron and wood. At some point, it must descend into the underground tunnels. The platform is streaked with bird shit. Pigeons are roosting everywhere, on the peeled-paint benches, in the old trash bins, between the tracks. A sun-faded and wind-battered sign must at one point have listed the station name; it is illegible now, but for a few letters: H, O, B, K. Old tags stain the walls: MY LIFE, MY CHOICE, says one. Another reads, KEEP AMERICA SAFE. Old slogans, old signs of the fight between the believers and the nonbelievers.

“What is this place?” I say to Rat-man. He’s crouching by the black mouth of the hole that leads below. He has flipped his hood up to shield his eyes from the sun, and he seems desperate to leap back into the darkness. This is the first time I’ve had a chance to really look at him, and I see now he is much younger than I’d imagined. Other than faint, crisscrossed lines at the corners of his eyes, his face is smooth and unlined. His skin is so pale it has the blue tint of milk, and his eyes are fuzzy and unfocused, unused to so much light.

“This is the landfill,” he says, pointing. About a hundred yards off, in the direction he indicates, is a tall chain-link fence, beyond which we can see a mound of glittering trash and metal. “Manhattan is across the river.”

“The landfill,” I repeat slowly. Of course: The underground people must have a way to gather supplies. The landfill would be perfect: heaps and heaps of discarded food, supplies, wiring, and furniture. I feel a jolt of recognition. I scramble to my feet. “I know where we are,” I say. “There’s a homestead nearby.”

“A what?” Julian squints up at me, but I’m too excited. I jog down the platform, my breath steaming in front of me, lifting my arm to shield my eyes from the sun. The landfill is enormous—several miles square, Tack told me, to service all of Manhattan and its sister cities—but we must be at its northern end. There’s a gravel road that winds away from its gates, through the ruins of old, bombed-out buildings. This trash pit was once a city itself. And less than a mile away is a homestead. Raven, Tack, and I lived here for a month while we were waiting for papers and our final instructions from the resistance about relocation and reabsorption. At the homestead there will be food, and water, and clothing. There will be a way to contact Raven and Tack, too. When we lived there we used radio signals, and, when those got too dangerous, different-colored cloths, which we raised on the flagpole just outside of a burned-out local school.

“This is where I leave you,” Rat-man says. He has swung his lower body back into the hole. I can tell he’s desperate to get out of the sun and go back to safety.

“Thank you,” I say. The words seem stupidly insufficient, but I can’t think of any others.

The rat-man nods and is about to swing himself down the ladder when Julian stops him.

“We didn’t get your name,” Julian says.

The rat-man’s lips twitch into a smile. “I don’t have one,” he says.

Julian looks startled. “Everyone has a name,” he says.

“Not anymore,” the rat-man says with that twitchy smile. “Names don’t mean a thing anymore. The past is dead.”

The past is dead. Raven’s refrain. It makes my throat go dry. I am not so different from these underground people after all.

“Be careful,” the rat-man says, and his eyes go unfocused again. “They’re always watching.”

Then he drops down into the hole. A second later the iron cover slides into place.

For a moment, Julian and I stand in silence, staring at each other.

“We did it,” Julian says finally, smiling at me. He is standing a little ways down the platform, the sun streaking his hair with white and gold. A bird darts across the sky behind him, a fast-moving shadow against the blue. There are small white flowers pushing up between the cracks in the platform.

Suddenly I find that I am crying. I am sobbing with gratitude and relief. We made it out, and the sun is still shining, and the world still exists.

“Hey.” Julian comes over to me. He hesitates for a second, then reaches out and rubs my back, moving his hand in slow circles. “Hey, it’s okay. It’s okay, Lena.”

I shake my head. I want to tell him that I know, and that’s why I’m crying, but I can’t speak. He pulls me into him and I cry into his T-shirt and we stand there like that, in the sun, in the outside world, where these things are illegal. And all around us there is silence, except for the occasional twittering of birds, and the rustle of pigeons around the empty platform.

Finally I pull away. For a second I think I see movement behind him, in the shadows beyond one of the station’s old stairwells, but then I’m sure I’ve only imagined it. The light is unrelenting. I can’t imagine what I must look like right now. Despite the fact that the underground people have cleaned and treated Julian’s wounds, his face is still patterned with bruises, a multicolored patchwork. I’m sure I look just as bad, if not worse.

Belowground, we’ve been allies; friends. Aboveground, I’m not sure what we are, and I feel uneasy.

Thankfully, he breaks the tension. “So you know where we are?” he says.

I nod. “I know where we can get help from—from my people.”

To his credit, he doesn’t flinch. “Let’s go, then,” he says.

He follows me down into the tracks. We startle the pigeons from their roost, and they whirl up around us, a blurry, feathered hurricane. We pick our way over the train tracks and onto the high grass beyond it, bleached pale from the sun and still sheathed in frost. The ground is hard and webbed with ice, although here, too, there is evidence of spring growth: small, curled buds of green, a few early flowers scattered among the dirt.

The sun is warm on our necks, but the wind is icy. I wish I had something warmer than a sweatshirt. The cold reaches right through the cotton, grabs on to my insides, and pulls.

Finally the landscape becomes familiar. The sun draws stark shadows on the ground—towering, splintered shapes of bombed-out buildings. We pass an old street sign, doubled over, that once pointed the way to Columbia Avenue. Columbia Avenue is now nothing more than broken slabs of concrete, and frozen grass, and a carpet of minuscule shards of glass, shattered into a reflective dust.

“Here it is,” I say. “Right up here.” I start jogging. The entrance to the homestead is no more than twenty yards away, beyond a twist in the road.

And yet, there’s another feeling drilling through me: some inner alarm sounding quietly. Convenient. That’s the word that keeps floating through my mind. Convenient that we ended up so close to the homestead; convenient that the tunnels led us here. Too convenient to be a coincidence.

I push away the thought.

We turn the corner and there it is. Just like that, all my concerns get whipped away on a surge of joy. Julian stops, but I go straight up to the door, recharged, full of energy. Most homesteads—at least the ones I’ve seen—have been built out of hidden places: basements and cellars and bomb shelters and bank vaults that remained intact during the blitz. We have populated them like insects reclaiming the land.

But this homestead was built long after the blitz was over. Raven told me it was one of the very first homesteads, and the headquarters of the first ragtag group of resisters, who scavenged for materials and built a quasi-house, a weird patchwork structure made from timber, concrete, stone, and metal. The whole place has a junky look, a Frankenstein facade, like it shouldn’t possibly be standing.