Emma pulled up his thin shirt. “The bleeding’s stopped,” she reported, “but he’ll die if he doesn’t see the inside of a hospital soon.”

“He may die anyway,” said Addison. “Especially in a hospital here in the present. Imagine: he wakes up in three days’ time, side healed but everything else failing, aged two hundred and bird-knows-what.”

“That may be,” Emma replied. “Then again, I’ll be surprised if in three days’ time any of us are alive, in any condition whatsoever. I’m not sure what more we can do for him.”

I’d heard them mention this deadline before: two or three days was the longest any peculiar who’d lived in a loop could stay in the present without aging forward. It was long enough for them to visit the present but never to stay; long enough to travel between loops but short enough that they were never tempted to linger. Only daredevils and ymbrynes made excursions into the present longer than a few hours; the consequences of a delay were too grave.

Emma rose, looking sickly in the pale yellow light, then tottered on her feet and grabbed for one of the train’s stanchions. I took her hand and made her sit next to me, and she slumped against my side, exhausted beyond measure. We both were. I hadn’t slept properly in days. Hadn’t eaten properly, either, aside from the few opportunities we’d had to gorge ourselves like pigs. I’d been running and terrified and wearing these damned blister-making shoes since I couldn’t remember when, but more than that, every time I spoke Hollow it seemed to carve something out of me that I didn’t know how to put back. It made me feel tired to a degree that was wholly new, absolutely subterranean. I’d discovered a fresh vein inside me, a new source of power to mine, but it was depletable and finite, and I wondered if by using it up I was using myself up, too.

I’d worry about that another time. For now I tried to savor a rare moment of peace, my arm around Emma and her head on my shoulder, just breathing. Selfishly, perhaps, I didn’t mention the hollow that had chased our train. What could any of us do about it? It would either catch us or not. Kill us or not. The next time it found us—and I was sure there would be a next time—I would either find the words to stay its tongues or I wouldn’t.

I watched Addison hop onto the seat across from us, unlock a window with his paw, and crack it open. The angry sound of the train and a warm funk of tunnel air came rushing in, and he sat reading it with his nose, eyes bright and snout twitching. The air smelled like stale sweat and dry rot to me, but he seemed to catch something subtler, something that required careful interpretation.

“Can you smell them?” I asked.

The dog heard me but took a long moment to reply, his eyes aimed at the ceiling as if finishing a thought. “I can,” he said. “Their trail is nice and crisp, too.”

Even at this high speed, he could pick up the minutes-old traces of peculiars who’d been enclosed in an earlier train car. I was impressed, and told him so.

“Thank you, but I can’t take all the credit,” he said. “Someone must’ve pushed open a window in their car, too, otherwise the trail would be much fainter. Perhaps Miss Wren did it, knowing I would try to follow.”

“She knew you were here?” I asked.

“How did you find us?” Emma said.

“Just a moment,” Addison said sharply. The train was slowing into a station, the windows flashing from tunnel black to tile white. He stuck his nose out the window and closed his eyes, lost in concentration. “I don’t think they got off here, but be ready in any case.”

Emma and I stood, doing our best to shield the folding man from view. I saw with some relief that there weren’t many people waiting on the platform. Funny there were any at all, or that trains were still running. It was as if nothing had happened. The wights had made sure of it, I suspected, in hopes we’d take the bait, jump onto a train, and make it simple for them to round us up. We certainly wouldn’t be hard to spot amongst modern London’s workday commuters.

“Look casual,” I said. “Like you belong here.”

This seemed to strike Emma as funny, and she stifled a laugh. It was funny, I guess, inasmuch as we belonged nowhere in particular, least of all here.

The train stopped and the doors slid open. Addison sniffed the air deeply as a bookish woman in a pea coat stepped into our car. Seeing us, her mouth fell open, and then she turned smartly and walked out again. Nope. No thanks. I couldn’t blame her. We were filthy, freakish-looking in bizarre old clothes, and splashed with blood. We probably looked like we’d just killed the poor man beside us.

“Look casual,” Emma said, and snorted.

Addison withdrew his nose from the window. “We’re on the right track,” he said. “Miss Wren and the others definitely passed this way.”

“They didn’t get off here?” I asked.

“I don’t think so. But if I don’t smell them in the next station, we’ll know we’ve gone too far.”

The doors smacked closed and with an electric whine we were off again. I was about to suggest we find a change of clothes when Emma jolted beside me, as if she’d just remembered something.

“Addison?” she said. “What happened to Fiona and Claire?”

At the mention of their names, a nauseating new wave of worry shot through me. We’d last seen them at Miss Wren’s menagerie, where the elder girl had stayed behind with Claire, who was too ill to travel. Caul told us he’d raided the menagerie and captured the girls, but he also told us Addison was dead, so clearly his information couldn’t be trusted.