‘I know who she is,’ he said gently. ‘It’s half eleven – she’ll already be asleep, won’t she? A couple of minutes. It’s about Rin.’

She looked at him: really? What else would it be about? ‘Fine, a quick one, but let’s walk. I need to get out of here.’

He followed her into the corridor. It was wide and empty, lights reflecting blankly off lino and gloss-painted walls, but Robin could feel the hospital around them, a huge engine humming in the night, like a cross-Channel ferry, or a giant animal, warm and slow-breathing, protective. They walked for a moment, putting distance between themselves and the ward. Their footsteps echoed.

‘You knew I was here,’ she said, stopping. ‘You’re on this, aren’t you?’

‘The case? No.’

‘But you’re Head of Homicide.’

‘The SIO’s a guy called Webster. He’s very experienced; he—’

‘DI Webster, yes, I saw him on the news. It’s not a domestic.’

He took a breath. ‘Do you think I’d give it to someone who couldn’t handle it? Not just handle it – do it well.’

‘Do you think it’s being done well? DS Thomas asked if I was sleeping with Josh. Yesterday.’

The words stole the oxygen between them for a moment, and she felt blood rush to her face. He broke the eye contact, looked away. Up ahead, the double doors swung open and a porter came through wheeling an empty bed. They waited for him to pass.

‘I heard what your father saw,’ he said. ‘Rin with the black eye. You told Thomas and Patel yourself he’s a reliable witness.’

‘Husbands aren’t the only people who hit women.’ Her cheeks were burning.

‘No, but most women who are hit are hit by their partners.’

‘You really think he hit her? Come on.’

‘You really think she was getting into fights?’

‘I don’t know.’ She shrugged. ‘It’s not impossible, she could be fierce. She could fight if she wanted to. And who said she was hit, even? There are other ways to get black eyes.’

He stopped. ‘Look, Robin, I don’t want to believe this. I really don’t. That’s why I’m here. I’m asking you to help us. Me.’

She met his eye and for a moment, she had the feeling she was looking into a palimpsest, layer after layer of shifting memories, moving over each other like slides loose in a box.

‘Please,’ he said. ‘Even if for some reason you couldn’t tell Thomas and Patel, tell me. Tell me something that’ll help us prove Josh didn’t do it.’

‘I can’t,’ she said.

‘Can’t or won’t?’

‘You think I’m withholding information?’

His turn to shrug, but with a strange half-smile. ‘That’s how mad this is. If it meant we could prove my friend didn’t kill his wife, I would actually hope you are.’