Coming down from the terrifying events of that evening, I’d reached a new low of exhaustion. My head tingled strangely. My feet dragged. The rumble of bombs had quieted and the sirens had finally wound down, and I wondered if all that apocalyptic noise had been keeping me awake. Now the smoky air was alive with subtler sounds: water gushing from broken mains, the whine of a trapped dog, hoarse voices moaning for help. Occasionally fellow travelers would materialize out of the dark, wraithlike figures escaped from some lower world, eyes shining with fear and suspicion, clutching random things in their arms—radios, looted silver, a gilt box, a funerary urn. Dead bearing the dead.

We came to a T in the road and stopped, the pigeon deliberating between left and right. The girl murmured encouragements: “Come on, Winnie. There’s a good pigeon. Show us the way.”

Enoch leaned in and whispered, “If you don’t find Miss Wren, I will personally roast you on a spit.”

The bird leapt into the air, urging left.

Melina glowered at Enoch. “You’re an ass,” she said.

“I get results,” he replied.

Eventually we arrived at an underground station. The pigeon led us through its arched entry into a ticket lobby, and I was about to say We’re taking the subway—smart bird, when I realized the lobby was deserted and the ticket booth shuttered. Though it didn’t look like trains would be visiting this station anytime soon, we forged ahead regardless, through an unchained gate, along a hallway lined with peeling notices and chipped white tiles, to a deep staircase where we spiraled down and down into the city’s humming, electric-lit belly.

At each landing, we had to step around sleeping people wrapped in blankets: lone sleepers at first, then groups lying like scattered matchsticks, and then, as we reached bottom, an unbroken human tide that swept across the underground platform—hundreds of people squeezed between a wall and the tracks, curled on the floor, sprawled on benches, sunk into folding chairs. Those who weren’t sleeping rocked babies in their arms, read paperbacks, played cards, prayed. They weren’t waiting for a train; no trains were coming. They were refugees from the bombs, and this was their shelter.

I tried sensing for hollows, but there were too many faces, too many shadows. Luck, if we had any left, would have to sustain us for a while.

Now what?

We needed directions from the pigeon, but it seemed briefly confused—like me, it was probably overwhelmed by the crowd—so we stood and waited, the breaths and snores and mumbles of the sleepers murmuring weirdly around us.

After a minute the pigeon stiffened and flew toward the tracks, then reached the end of its leash and bounced back into Melina’s hand like a yo-yo.

We tiptoed around the bodies to the edge of the platform, then hopped down into the pit where the tracks ran. They disappeared into tunnels on either end of the station. I had a sinking feeling that our future lay somewhere inside one of these dark, gaping mouths.

“Oh, I hope we don’t have to go mucking about in there,” said

Olive.

“Of course we do,” Enoch said. “It isn’t a proper holiday until we’ve plumbed every available sewer.”

The pigeon bopped rightward. We started down the tracks.

I hopscotched around an oily puddle and a legion of rats scurried away from my feet, sending Olive into Bronwyn’s arms with a shriek. The tunnel yawned before us, black and menacing. It occurred to me that this would be a very bad place to meet a hollowgast. Here there’d be no walls to climb, no houses to shelter in, no tomb lids to close behind us. It was long and straight and lit only by a few red bulbs, glinting feebly at scattered intervals.

I walked faster.

The darkness closed around us.

*   *   *

When I was a kid, I used to play hide-and-seek with my dad. I was always the hider and he the seeker. I was really good at it, primarily because I, unlike most kids of four or five, had the then-peculiar ability to be extremely quiet for long periods of time, and also because I suffered from absolutely no trace of anything resembling claustrophobia: I could wedge myself into the smallest rear-closet crawl space and stay there for twenty or thirty minutes, not making a sound, having the time of my life.

Which is why you’d think I wouldn’t have a problem with the whole dark, enclosed spaces thing. Or why, at the very least, you’d think a tunnel meant to contain trains and tracks and nothing else would be easier for me to handle than one that was essentially an open cemetery, with all manner of Halloweenish things spilling out along it. And yet, the farther into this tunnel we walked, the more I was overcome by clammy, creeping dread—a feeling entirely apart from the one I sensed hollows with; this was simply a bad feeling. And so I hurried us through as fast as the slowest of us could go, prodding Melina until she barked at me to back off, a steady drip of adrenaline keeping my deep exhaustion at bay.

After a long walk and several Y-shaped tunnel splits, the pigeon led us to a disused section of track where the ties had warped and rotted and pools of stagnant water spanned the floor. The pressure of trains passing in far-off tunnels pushed the air around like breaths in some great creature’s gullet.

Then, way down ahead of us, a pinpoint of light winked into being, small but growing fast. Emma shouted, “Train!” and we split apart and pressed our backs to the walls. I covered my ears, expecting the deafening roar of a train engine at close range, but it never came—all I could hear was a small, high-pitched whine, which I was fairly certain was coming from inside my own head. Just as the light was filling the tunnel, its white glow surrounding us, I felt a sudden pressure in my ears and the light disappeared.

We stumbled away from the walls in a daze. Now the tracks and ties under our feet were new, as if they’d just been laid. The tunnel smelled somewhat less intensely of urine. The bulbs along it had gotten brighter, and instead of giving a steady light, they flickered—because they weren’t electric bulbs at all, but gaslamps.

“What just happened?” I said.

“We crossed into a loop,” said Emma. “But what was that light? I’ve never seen anything like that.”

“Every loop entrance has its quirks,” said Millard.

“Anyone know when we are?” I asked.

“I’d guess the latter half of the nineteenth century,” said Millard. “Prior to 1863 there wasn’t an underground system in London at all.”

Then, from behind us, another light appeared—this one accompanied by a gust of hot wind and a thunderous roar. “Train!” Emma shouted again, and this time it really was. We threw ourselves against the walls as it shot past in a cyclone of noise and light and belching smoke. It looked less like a modern subway train than a miniature locomotive. It even had a caboose, where a man with a big black beard and a guttering lantern in his hand gaped at us in surprise as the train strafed away around the next bend.

Hugh’s cap had blown off his head and been crushed. He went to pick it up, found it shredded, and threw it down again angrily. “I don’t care for this loop,” he said. “We’ve been here all of ten seconds and already it’s trying to kill us. Let’s do what we have to and get gone.”

“I couldn’t agree more,” said Enoch.

The pigeon guided us on down the track. After ten minutes or so, it stopped, pulling toward what looked like a blank wall. We couldn’t understand why, until I looked up and noticed a partially camouflaged door where the wall met the ceiling, twenty feet overhead. Because there seemed no other way to reach it, Olive took off her shoes and floated up to get a closer look. “There’s a lock on it,” she said. “A combination lock.”

There was also a pigeon-sized hole rusted through the door’s bottom corner, but that was no help to us—we needed the combination.