He rubbed distractedly at his left arm, stretching his bicep then flexing his hand. “Have to confess, that climb took it out of me. Feeling my years, ha. Hold up, what’s this?” Spotting the dead flier, Alex’s grandfather leaned forward, scrutinizing the thing. “Where did he come from?” He scanned the sky in alarm.

“Don’t know,” Alex said. He could barely feel his arms. “Uh. Could you help? I can’t hold on much longer.”

“Oh. Of course. Give me your hand, old bean.”

With help, Alex maneuvered until he was sitting facing his grandfather. The old man sat studying the robot pinned between them. Moving with great care, Alex bent to join him.

“I think I crashed into it, in the air, when the heel things threw me up,” Alex said. “Or maybe it was already on the branch and I landed on it.”

“In bad shape,” his grandfather mused. “What do you make of that?” As he flicked the scrap of black cloth, Alex suddenly remembered Carl, in his bedroom, holding up his hooded top, the rough little square hole cut out of the back. Gremlins come when they’re out on the clothesline.

“I think that’s . . . mine. Cut from my hoodie.” Moving with great care, Alex pulled at his hooded top to display the spot.

“Hmm. Wear it a lot?”

“All the time.”

His grandfather nodded. “Beginning to make sense. When I met you, you said you’d had a feeling you were being followed. You were. By this. How long did you say you’d felt it?”

“A week, maybe?”

“Uh-huh. They must have sent it to keep track of you. My father or Zia, but most likely him. He knows where your house is now. He knows you exist now, more to the point. He didn’t before the golem business; I’d always tried to keep you— Well, anyway, this explains how they knew we were going to Harry’s office. Why they were waiting.”

“They can see us through these things?” Alex asked, shifting on the branch. “I’ve never really understood it.”

“Well, depends on the type of device, and how close to us it got. And, most of all, who’s operating it,” his grandfather said, still distracted. “Ah, what kind of skill, what power they have. It’s a combination of natural talent, study, and practice, like most things. A low-level practitioner could just give the machine a basic instruction and would then have to watch and direct it: like operating a remote-control airplane, say. But, yes, at higher levels, when you learn to section off your mind, and have the strength, you can send out part of your awareness. A psychic extension—”