Children appear from corridors like ants, dressed in hats and scarves although spring is here. Lizzie remembers the damp smell of wool on radiators, the warmth she drew from being with children. She was never awkward with them. She didn’t need to be their friend, she needed to be their teacher, but she became both. Her notice-board was always full of cards from her class. ‘To the best teacher in the whole (infinite) universe’ and ‘You are even cleverer than The Guinness Book of Records.’

Lenny says nothing, but cranes his head, taking it all in. He’s small for his age, the borrowed clothes too big. Lizzie wants to scoop him up in her long cardigan and take him home. She wants his nose in her neck. A shelter is no place for a kid, Lizzie. She knows that. He needs to be at school. Making friends. Learning. He wants to eat the whole world and she can only offer him the tiniest sliver, a waning crescent. She feeds him encyclopaedias. Sets the timer on his T-Rex watch, five facts in ten seconds. She fills his brain with statistics and trivia. Did you know pigs can’t look up? Monkeys go bald in old age? Kangaroos can’t walk backwards? She tells him that you can make dynamite with peanuts. The word ‘muscle’ means ‘little mouse’ in Latin, because that is what ancient Romans thought biceps looked like. Bodies give off a light too weak for the eye to see.

The details fall through him, like water in a sieve. Hey, Lenny, your heart is the same size as your fist. Lenny’s fist is tiny, but his heart is huge, and there is a tear in the muscle, a mouse hole, that only his dad can fill.

‘Ah, Lenny,’ says an overly made-up receptionist wearing a badge that says Linda, ‘I’ve been looking forward to meeting you. I hear you like football.’ She gives him a conspiratorial wink and adds, ‘I know some boys who badly need a good left-footer.’

‘I’m left-footed!’ Lenny blurts out. Linda smiles over his head at Lizzie, who mouths, ‘Thank you,’ and breathes slightly easier.

‘How about that, then?’ Linda says. ‘Come on, kiddo, it’s almost time for break. Mum will be back to pick you up at three fifteen, okay?’