“Do you know where you are?” I said. “Do you come from here?”

In reply, she pointed to the crack in the floor. Even the act of pointing to the crack distressed her again, and she began to cry . . . except she couldn’t cry. She just heaved and made a noise like air slowly leaking from a bike tire.

“Aurora?” Claudia called. “Are you down here?”

I had absolutely no idea what to do about this situation. But the woman was clearly distressed, so I did what I had seen Boo do—I reached out to her to try to calm her down before Claudia came into the room and this conversation was over.

“Come on,” I said. “It’s okay—”

As soon as I made contact, I felt a crackle, like a static shock. I couldn’t move my arm. Something was running through it, something that felt like a current, something that made me stiffen in position. I had a feeling of falling, like a lurching elevator dropping between floors. The woman opened her mouth to speak, but before she could say anything, there was a rush of air around us and a roaring noise.

And then, there was the light—impossibly bright and filling the senses. It consumed us both. A moment after that, it blinked out. I fell backward, stumbling through the open doorway of the stall and just managing to catch myself before I fell over.

“Rory!” That was my mother’s voice, urgent. Claudia was saying something as well. My eyes were still adjusting. I could just make out shapes at first—the stall door, the window, the pattern of the tiles. The smell was already there, sweet, floral, almost like a scented candle. The unmistakable smell of a ghost departed. And as my eyes came back into focus, I saw that the woman was gone. I looked at the empty space, then at my hand.

“Rory?” my mother said. “What happened? What was that noise?”

That was not a question I was prepared to answer.

Acknowledgements

ACKNOWLEDGMENTS

I HAD THE IDEA FOR THIS BOOK ONE VERY HOT SUMMER’S DAY IN London. I shoved everything else aside and worked on it like a mad working thing. I talked about it a lot. I dragged people to dark alleys in the East of London to stare at walls and sidewalks. I made some of the same people watch hours of footage taken from the driver’s compartment of a Tube train (“Hey! This one is forty-five minutes of driving the Northern line tunnels! Grab a snack!”) I have depended on the following people in various ways, and they are all owed thanks.