It was difficult to keep track of time in the windowless library, but she thought it was getting on towards evening by the time they’d loaded the trolley with the last few springy pamphlets. Alice’s stomach was reminding her it was nearly dinnertime, in any case, and she was more than ready to get out of the old library and find a basin to wash off the clinging, all-pervading dust. For a library one mustn’t go into, this has been a real disappointment. There must be some interesting books in here, surely, but with nothing organized, they would be impossible to find. And there’s certainly nothing dangerous, unless Geryon was worried about the shelves collapsing on me.

There remained the task of piloting the trolley back to where Mr Wurms was waiting, which turned out to be no simple endeavour. The pile of books was taller than Alice’s head, so if she pushed from the back she couldn’t see where she was going, much less attempt to steer, and the thing weighed so much, it took ages to shove into motion and an equally long time to stop. Emma, at the front, walked in a sort of rolling crouch to drag the thing along and keep it pointed in the right direction, with Alice alternately shoving against the unyielding weight and hauling backwards when they were about to run into something.

Between them, Alice imagined they made quite an amusing spectacle, and she was privately glad there was no one to see them but the cats. It was therefore with some surprise that she heard, through the squeaking rattle of the metal beast, the definite sound of a snicker.

At first she thought she’d imagined it. It had been a long day, and she was hungry and getting cross. But it came again as they were rounding a corner, which entailed both girls hauling sideways on the trolley like cowboys wrestling an unruly stallion, and this time the sound was absolutely unmistakable. Alice thought briefly of the cats, and her feeling of being watched. But – though she was not an expert on cats – she was fairly certain that they did not, as a rule, snicker. She waited a few heartbeats, until they’d got the trolley straightened out, and then, fast as she could, looked over her shoulder.

There was a cat, a grey one, standing on a low shelf. It sat quite still, staring directly at Alice and looking extremely pleased with itself.

Something went thump up ahead. Alice spun round and pulled back on the trolley as hard as she could. Once she’d got it stopped, she hurried round it, and found Emma on the floor and doing her best to keep from being run over.

‘Sorry!’ Alice said, automatically, putting out a hand to help her up. ‘Are you all right?’