Opening the locker, I stepped into the cave darkness, flicked on my new flashlight, and crept down the hidden hallway. Lace’s and my footprints were still there, preserved in peanut butter, but no new ones had appeared.

I cut open the chained-up door again, and this time when I closed it behind me, I jammed wedges into the cracks, restuffing the steel wool underneath.

The site secured, I descended the stairs, flashlight in hand.

The swimming pool was almost quiet.

In the soft red glow I saw only a few dozen rats and the picked-clean skeletons of pigeons, sitting undisturbed. Apparently it wasn’t feeding time. The peep cat wasn’t in sight.

I found my abandoned duffel bag and I transferred a few necessary items to my new one, then stepped into the empty pool. My boots trod softly across the pigeon feathers. The few rats perching on the pool’s edge watched me descend toward the deep end, mildly curious. A big fat one leaned his chin over the diving board, looking down at me.

Without a thousand panicking rodents in the way, I could see the drain much better. The concrete around it had collapsed, and through the jagged hole was a deeper darkness that offered up a damp and earthy smell. No scent of death.

The hole was big enough for a slender human body to slip through. Hunkering at the edge, I opened a can of cat food. The smell of Crunchy Tuna infused the air, and I heard little noses sniffing around me. But nothing came to investigate.

Dr. Rat has a word for what rats are: neophobic. In other words, they don’t like new things. Related to them or not, I was something new in their environment, and Crunchy Tuna was too.

I pushed a chunk of Crunchy Tuna down into the hole. A liquid splat came from below. The space down there was big; I could hear its size in the echoes.

After a few minutes of waiting, I switched off the flashlight completely. Blind in the darkness, I hoped my ears might begin to listen harder. The few rats around me continued going about their business, cleaning themselves and squabbling. A few got up the courage to dart past me and down into the hole. They sniffed the dollop of cat food below, but I heard no little teeth daring to take a bite. They were a cautious bunch.

Rats send chemical signals to one another, emotions carried by smells. One nervous individual can make a whole pack of rats anxious, fear spreading through the population like a dirty rumor. And sometimes, a pack will suddenly abandon a place all at once, collectively deciding that it has bad vibes.

I wondered if the peep cat’s brood was still jittery from my flashlight blast the night before. Maybe they had left this basement forever, fleeing far down into the Underworld.

Then I heard the meow.

It reached me from a long distance, sleepy and annoyed-sounding, through a prism of echoes. The cat was still down here.

But it wasn’t coming to me; I had to go to it.

The concrete was brittle—a few solid kicks opened the hole enough for me to climb through. I lowered my duffel bag as far as possible, then dropped it. The clunk of metal told me that the floor was about ten feet below.

Holding onto the flashlight carefully, I slipped through and let myself fall. My boots hit solid ground with a crunch of shattered concrete that echoed like a gunshot.

I switched my flashlight on low again.

A tunnel stretched away into the darkness, extending as far as I could see in both directions. Decades of dust had settled in here, filling the bottom with a loose dirt floor. It was lined with uneven stones, century-old mortar barely holding them together. They were cold and wet to the touch—the tons of dirt over my head squeezing the groundwater through them like a fist around a wet rag.

A slight breeze moved through the passage, carrying the smells of rats, earth, and fungus. Still, nothing as foul and horrible as what I had scented the day before.

The breeze felt fresh; it had to be coming from some sort of opening at the surface. I decided to move upwind. With the air blowing into my face, I could smell whatever was in front of me without it smelling me.

I’ve been in a lot of underground spaces in New York—subway tracks, sewers, steam pipe tunnels—but this one was different. There were no stray bits of paper, no garbage, no smells of piss. Maybe it had lain undisturbed by human beings for the century since it had been built, carrying only air, rats, and the occasional peep cat beneath the city streets. The tunnel inclined slightly as I walked, a winding stain in the center of the floor showing where rain had trickled down the slope for the last hundred years.

Then I smelled something human on the breeze. Well… half human.

Peeps have a subtle scent. Their feverish bodies consume almost everything they eat, leaving few smells of waste. Their dry skin exudes none of the salty sweat of a regular person. But no metabolism is perfect—my predator’s nose detected a hint of rotten meat and the whiff of dead skin cells, like fresh leather hanging on a boot factory wall.

The breeze died and I froze, waiting for it to come again. I didn’t want my scent to drift ahead of me. A moment later, the air moved again, and the intimate smell of family washed over me.

This peep was a relative.

As softly as I could, I laid the duffel bag on the ground and pulled a knockout injector from the zippered pocket of my hazmat suit.

I switched off the flashlight and began to crawl, a wave of nerves rushing through me. This was the first peep I’d ever hunted who was an absolute unknown. The only anathema I had was the Garth Brooks T-shirt, which somehow didn’t seem equal to the task. The darkness seemed to stretch forever before me, until a hint of light played across the blackness. Gradually I was able to make out the stones in the passage walls again, and my hands in front of my face … and then something else.

What looked like tiny clouds were rolling along the floor, carried by the breeze. They glided toward me, silent and insubstantial, and when I waved a hand close to them, they stirred in its wake.

Feathers.

I took a pinch and held it up to my eyes. This was the soft white down from a pigeon’s breast. As the light grew longer, I saw that the whole tunnel was carpeted with downy feathers; they clung to the ceiling stones and to my hazmat suit, rolling across the floor like a slow, ghostly tide.

Somewhere ahead, there were a lot of dead birds.

Larger feathers began to appear, the dirty gray and blue of pigeon and seagull wings, trembling in the breeze. I crawled silently across the carpeted dirt floor, feeling the softness under my palms and trying not to think of pigeon mites.

Ahead I could hear breathing, slow and relaxed for a peep.

The tunnel ended at a shaft that went straight up—light pouring down from above, a rusted iron ladder driven into the stone wall. A pile of feathers had collected at the bottom. A few whole birds lay on top of it unmoving, their necks twisted.

I froze, watching the breeze stir the feathers until a shadow moved across them. The peep was at the top of the ladder.

With the chill autumn air flowing down the shaft, it still couldn’t smell me. I wondered why it was nesting up there, instead of hiding down here in the gloom. Placing my flashlight on the floor to free up my hands, I crawled to the end of the tunnel and peered up, eyes slitted against the sunlight.

He clung to the ladder twelve feet above me, staring out at the world like a prisoner at a cell window, the reddish light of late afternoon softening his emaciated face.

I lowered myself into a crouch, gripped the injector, and jumped straight up as high as I could.

He heard me at the last second, looking down just as I reached up to jam the needle into his leg. He twisted away, the injector missing completely. My hand grasped the ladder but the peep screamed and flailed his foot at me, landing a kick in my teeth. My grip loosened … and I was falling.