“I have no idea. I’ve never done it before.” I held up Rabid. “Imagine magic as a frozen lake, one which coexists with the world around us. The book is the auger that helps us drill through the surface, and that hole gives definition to the energy beneath.”

“Magic as ice fishing. That’s different.”

“Every copy of this book chips away at the same hole, including the one our killer has been working with.”

“You can spy on him through that hole? Through your copy of the book?”

“In theory.” It violated half the rules of libriomancy, but there was precedent. “Gutenberg did it once, back in World War II. He used a copy of Mein Kampf to gather intelligence about the Germans. Every copy of the book becomes a kind of magical bug.” As I understood the story, that experience had come dangerously close to killing him. Drowning him, to extend the metaphor. Magical objects dissolved back into energy when returned to their books. What would happen to my mind if I lost my mental grip and slipped beneath the ice?

The only consolation was that I probably wouldn’t last long enough to know I had failed.

“I know that look,” Lena said. “What aren’t you telling me? How am I supposed to help if I don’t know—”

“You can’t help,” I snapped, and instantly regretted it. I opened the book and started reading.

Lena plucked it out of my hands and read the back. “So what’s the risk? Are you going to infect yourself with this virus? If so, we can find another way. I’m not watching you die.”

I shook my head. “The danger isn’t physical. Even if I succeed . . . there’s a possibility that something might come back through me.”

“You’re worried about being possessed, like Gutenberg?”

I didn’t bother trying to snatch the book away from her. “If I do this, we have a shot at finding him. If I lose myself, you can drag my body back to the vampires. All I know is that if I don’t try, Doctor Shah dies.”

Lena stiffened. She gripped the book with both hands. For a moment, I thought she might refuse to return it. A part of me hoped she would. But she reached out, offering the book back to me.

Neither of us spoke. There was no need.