“Like riding a bike.” The old man beamed as he touched down following his fourth test leap. He nodded, satisfied, then knelt to unstrap the contraptions. As he bent to stow them back in his Gladstone, he hesitated, set them aside on the ground, and pulled out the painting Harry had salvaged. The old man unrolled it and moved into better light to stand scrutinizing it.

“Can you show me those pictures you took of the others, Alex?”

While Alex found the images on his phone, his grandfather spread the canvas on the grass. Alex showed him yet again how to flip from one picture to another. After some grumbling, the old man got it, then crouched over the painting, stabbing at the screen.

“What am I missing?”

“Well, we don’t know if it’s all of them, do we?” Alex asked. “Like you said: we don’t know if they need all the paintings or just one, or what. Maybe there’s a connection between just some of them. So, like, uh: some have got people, and some don’t. Some have got trees, and some don’t.” Alex looked at the trees around them, thinking hard. “Maybe it’s to do with the different types of trees? You can make a recipe using leaves or . . . bark or something. Like with that flower you mentioned. The potion.”

“Hmm.” His grandfather sounded unconvinced. He pushed back his hat as he swiped rapidly at the phone, muttering.

Alex stood looking on over the old man’s shoulder. “Maybe it’s not . . . the pictures,” he said.

“Eh? How do you mean.”

“I mean, not the . . . images. Like, if it was some coded message in the images—to do with the trees, or whatever—they wouldn’t need to physically take the paintings, would they? They could just, y’know”—he gestured at the phone’s display—“look at copies.”

“That’s a point,” the old man said. “But then, there are minute details in the originals that might not be apparent in reproductions. And also, unless you were very careful and did them yourself, copies wouldn’t all be at the right scale to each other. These pictures on your phone certainly aren’t. What I’m saying is, you might need to arrange the originals together in a certain way, so that things line up in a particular manner. But, yes, decent point: they seem to need the actual physical object. Let me keep thinking.”