Harry shook his head, frowning gravely. Alex thought hard. He slipped Harry’s watch from his wrist.

“Is it okay if I use this?”

“’Ow’d you get that?” Harry pulled back his sleeve and stared in surprise at his empty wrist. “Your grandad been teachin’ you pick-pocketin’? But, yeah, go on. Whatever you’re doin’.”

Alex double-checked the strap was fastened, then hung it over the flier’s upraised scalpel-arm and sent the thing flying again. He slowed when he spotted his grandfather, heading determinedly along the road. The old man halted and lifted his stick as Alex descended, then paused, hovering at eye-level ten feet in front of him. His grandfather glanced around, turned back, regarding him cagily.

As slowly as he could, Alex lowered himself almost to the ground and let Harry’s watch slide gently to the pavement. He bobbed back up and retreated another ten feet.

The effort of controlling the flier was really beginning to tire him. He could feel every beat of a wing, every inch of the distance between himself and his machine. Hovering motionless like this took it out of him more than anything else.

The old man scowled, then lowered his stick and stood leaning on it, regarding the scene. Eventually, he came cautiously forward. A few steps from the watch, he dropped to a crouch and reached out, poking it warily with the cane. Finally, with care, he fished it up and pulled it to him. He straightened, examining the watch, pulled at his bottom lip, then cast another searching glance Alex’s way.

Alex turned slowly in the air, seeking inspiration. Nearby, the scraggy hedge ran along the field. He buzzed quickly over to it, scanning the ground, until he found a slender broken twig, almost a foot long. After a few efforts, he managed to work his clumsy hook into it and carried it back.

His grandfather stood watching. Alex approached gingerly until he was within five feet, then shook the twig free so it fell to the road. The old man pushed back his hat, baffled. Alex hunted for another twig much the same and dropped it on top of the first, then repeated the operation with a third, smaller, twig.

After making sure his grandfather wasn’t going to smash him to pieces, he hovered low, pushing and pulling the twigs on the road with his scalpel until they formed an A. He retreated several feet. His grandfather stared at him. Alex bobbed forward slowly, trying to nod at the A. The old man rubbed his chin.

After a few seconds, Alex moved in again. He hooked up the smaller twig and pulled it away, then rearranged the remaining two: X.

His grandfather stared at it dubiously, then gave Alex a long, pensive look. The old man moved to the side of the road by the spot Alex had marked, dropped his Gladstone, and, with a curt nod, sat on the bag, waiting.