“I’ll try. Are you sure you don’t want to sit down?” Maybe she could be helped—maybe she wasn’t so far along that the effects of the passport couldn’t be reversed, or at least, stabilized.

She looked down, rummaged in the inside of her denim jacket, and came out with a folded sheet of neon-yellow paper, rather dog-eared and stained. “I wasn’t worried until I saw these. I thought everything was going like it was supposed to. But then I read—” She stopped and swallowed. “I read these. And I knew that it wasn’t okay. That I have it.”

I took the paper from her. As I unfolded it, I asked, “Have what?”

Tiamat drew a sharp breath, as if she meant to use it in snapping at me. But a cough interrupted. When she was done, she said, “The—the disease. Like that.” She nodded at the paper.

Rico had mentioned, last night, that flyers had been posted all over town. This was one of them. I tried to read the warnings, the description of symptoms, the recommendations, but they kept going in and out of focus. This was a much more comprehensive list of symptoms and consequences than Ms. Wu had recited for the Ticker and me, I could tell that much. Of course, now that Ms. Wu had seen the end of the disease as well as the beginning, she had a better idea what it could do.

“I have it, don’t I?” Tiamat asked, her voice bobbing and cracking.

In my mind I held up her white, frightened face to Tick-Tick’s; then to the face of the girl in the Bolt Street Clinic. I had been so stupid. I had asked the wrong question. I’d wanted to find the drug that had killed her, but of course, she hadn’t been killed by a drug. She’d been killed by a virus. The evolving half-humans, with their underdeveloped, un-fey immune systems, were the vector that Ms. Wu had speculated on.

“Yes,” I said. “You have it.”

I’d asked the wrong question. I could ask the right one now, and find out where the passport was. Did I want to do that? I had no obligation to, I realized. It was my choice, and Rico would know I’d made it only if I chose to tell her.

The girl who waited, still barely hopeful, on the sidewalk in front of me had nothing to do with that choice. She was an imperative, the responsibility of life for life.

I stood up. “Come on,” I said to Tiamat, “we have to get you to a hospital.”

And as I dusted the grit off the back of my jeans, I asked the question. Thataway, Thataway, Thataway. It was all over town.

Chapter 10. Ghost of a Chance