‘Me too: doctor’s appointment. But this won’t take long.’ He paused. ‘Look, if you don’t want to …’

‘All right,’ she said. Her shoulders were slumped. ‘Maybe you’re right.’

Too late, Rebus was having second thoughts. It was as if the fight had gone out of her. He thought he knew the reason, but knew also that there was little he could do about it.

‘Great,’ he said.

Reynolds and Davidson were watching from one of the other desks. ‘Look, Shug,’ Reynolds said, ‘it’s the Dynamic Duo!’

It seemed to take all Ellen Wylie’s effort to lift her from her chair.

He briefed her in the car. She didn’t ask much, seemed more interested in the passing parade of pedestrians. Rebus left the Saab in hotel parking and walked into the Caledonian, Wylie a couple of steps behind.

The ‘Caley’ was an Edinburgh institution, a red-stone monolith at the west end of Princes Street. Rebus had no idea what a room cost. He’d eaten in the restaurant once, with his wife and a couple of friends of hers who were honeymooning in the city. The friends had insisted on putting dinner on their room tab, so Rebus had never known the final figure. He’d been uncomfortable all evening, right in the middle of a case and wanting to get back to it. Rhona knew, too, and excluded him from the conversation by concentrating on reminiscences she shared with her friends. The honeymooners holding hands between courses, and sometimes even while they ate. Rebus and Rhona almost strangers to one another, their marriage faltering …

‘How the other half live,’ he said to Wylie as they waited for the receptionist to call the Costellos’ room. When Rebus had phoned David Costello’s flat, there’d been no answer, so he’d asked around the office and been told that the parents flew into town Sunday evening, and that their son was spending the day with them.

‘I don’t think I’ve been inside before,’ Wylie replied. ‘It’s just a hotel, after all.’

‘They’d love to hear you say that.’

‘Well, it’s true, isn’t it?’

Rebus got the feeling she wasn’t thinking about what she was saying. Her mind was somewhere else, the words just filling spaces.

The receptionist smiled at them. ‘Mr Costello’s expecting you.’ She gave them the room number and directed them towards the lifts. A liveried porter was hovering, but one look at Rebus told him there was no work for him here. As the lift glided upwards, Rebus tried to get the song ‘Bell-Boy’ out of his head, Keith Moon growling and wailing.

‘What’s that you’re whistling?’ Wylie asked.

‘Mozart,’ Rebus lied. She nodded as if she’d just placed the tune …