‘But also Corinna was here,’ said Dennis. ‘Mohammed couldn’t go to the mountain this time, she had a husband and her son and a job, so the mountain had to come here. At crisis point, it’s always been Corinna Robin wanted. Sometimes I think she was the only person she ever really trusted.’

Robin turned over, pushing the duvet off with her foot. Her mouth was dry again so she reached for the glass of lukewarm water on the floor. There was no middle way: she would either have to wake up parched – if she slept at all – or get up three times in the night to pee.

She lay back down, trying to find a cooler spot on the pillow. Overhead, Lennie was sleeping on her back – she could tell by the slight catch in her breathing. She focused on the gentle rhythm, tried to match it. In the gloom, the slats of the upper bunk were railway tracks, the lid of a box, the trapdoor over the oubliette. There was a line of old glow-star stickers along one of them, edges curling, luminosity years gone. She’d been looking at them for an hour and a half already; she’d come up as soon as she could after the police had left, needing a door between her and the world to try to think.

What she knew for certain: the black eye wasn’t an accident. If it had been, Corinna wouldn’t have hidden it. At the garage with Dennis, she’d have paraded it, made self-deprecating jokes: Guess which bit of human plankton left the bathroom cabinet open? But more than that, she’d have told Robin. Triumphs, humiliations – they’d shared everything. Corinna had seen her unwashed, lank-haired, wired up to the breast pump in a sports bra with the nipples cut out. Rin was protective of her dad, she didn’t tell anyone about him, but she’d confided in her about the times he’d fallen down the stairs or puked at the dinner table; collapsed on the landing with his trousers round his knees. They shared the big stuff but also the small: a funny present for Josh’s Christmas stocking; Gid’s better jokes; Lennie and Peter’s wobbly teeth, swimming badges, childish sayings – they’d gone back and forth every day. An accidental black eye would have been comedy gold.

So it was deliberate, she’d tried to hide it. But an accident was nothing to hide. Being mugged was nothing to hide. Getting lamped by a nutter who thought you’d looked at him funny was nothing to hide.