‘Here,’ he said, handing her a scrap of paper covered in his neat handwriting. It was a set of directions to a shelf, and a list of titles. ‘Find these and bring them back.’

‘Are there magic scraps in them?’ Alice said.

‘Never mind what’s in them,’ Mr Wurms said. ‘Just do as you’re told.’

Ashes slipped past her, rubbing against her ankle, and curled up underneath the table for a nap. Alice turned away with an inward sigh and headed back into the maze of shelves.

After lunching on a packet of sandwiches she’d brought from the kitchen, Alice settled down in a quiet spot to spend some time practising with the swarmers. A soft tug on the thread called one into being with a soft pop, and a harder yank created a cascade of the little things. They stood in a semicircle around her, bright black eyes staring, quirking softly and waiting obediently for orders.

Though it wasn’t really like she gave them orders, exactly. It was more like she’d acquired another limb. All she had to do was think, and the creatures would rush to obey, though getting them to do precisely what she wanted was sometimes as difficult as threading a needle.

She made them rush one way, then another, running full tilt into a bookshelf and bouncing off in an explosion of rubbery little bodies. They were almost impossible to injure, Alice had found. Any attempt to squash them just sent them bouncing off in another direction, like a rubber ball, and they always rolled back to their feet in moments, ready for more.

Those beaks were sharp too. She’d thrown them the wrapping from one of her sandwiches as a test, and they’d torn it to shreds in seconds, filling the air with flying bits of paper. Alice shuddered to think what would have happened to her and Ashes if they’d been caught.

Today she was trying to get them to climb a bookshelf. The wood was too hard for their little claws to grip, and they weren’t good jumpers, but Alice had hit on the idea of piling them up in a sort of pyramid. They climbed onto one another’s backs readily enough, but keeping the whole structure stable required paying attention to all of them at once, and the first few times she tried it, they quickly collapsed into a pile of squirming, bouncing bodies.

Eventually she managed to keep them steady enough that a single intrepid swarmer managed to scurry up to the very top of the pyramid and clamber onto a shelf higher than Alice’s arms could reach. She waved to it, grinning in triumph. The swarmer stood stolidly, looking back at her, waiting for further instructions.

Alice let all the rest of them vanish, with a noise like cooking popcorn, and regarded the one on the shelf.