Linn looked startled. It was an expression so much like one of Tick-Tick’s that I smiled. He’d been so busy unravelling the fine points of “how” that “why” had never come up. The Ticker was the same way, given some complex puzzle to work out, or some delicate structure to assemble—

There are times when the light bulb goes on over your head so emphatically that you can hear the pull chain click. “Because it wasn’t meant for us.”

They both turned to stare at me, but it was Linn who said, “So sure?”

“Well, it couldn’t have been. Charlie’s keys led us here. But Charlie’s keys wouldn’t have done jack if I hadn’t been involved, and I wasn’t involved until maybe an hour before we showed up at this place. And that,” I finished, pointing at the wires and battery holder, “wasn’t set up in an hour, was it?”

“Indeed, no. The ceiling was patched after the trap was laid, and there was no sign that the fallen plaster was still wet.”

“So who was it for?” Rico asked.

I shrugged. “They were Charlie’s keys.”

She thought about that. “Okay. This starts to make sense. Assume our illusion-maker doesn’t realize that I’m watching Charlie already. Also understand that if somebody blows up a building, even in Soho, we all kind of notice, but that a building falling down from rot and old age is common enough that we wouldn’t think much about it. Whoever it is wants to dispense with Charlie and not attract too much attention to him post mortem. So, a shame about him being in that old building when it collapsed, or, gee, his friends warned him about being stoned on top of tall things.”

“So this was just the leftovers.” I fingered the photocell through its plastic bag. “But why was it still here? Once Charlie was dead…”

“You already explained that. They thought they had plenty of time. They didn’t know we had you.”

Linn was contemplating me with a sort of interested pity, much like his reaction when I’d passed out in the morgue. “You have led us to a place we should not have found. You have brought Charlie’s last moments out of the past, and with them, the proof that his death was not an accident. Our quarry will know soon, if he does not yet, that you are a danger to him.”

I suppose I’d already figured that out. Or at least, I would have shortly, just as soon as I could have seen past the puzzle itself to the consequences. I was getting to be as bad as Tick-Tick.

“Why the note?” Rico said, and I tried to concentrate on that. “There wasn’t anything like it on the Pigeon Cloisters roof. And why a melodramatic, “So long, sucker” message, anyway?”

“Let me see it,” said Linn.