Ping. No rush. The next hour will do. Finish your drink and take the dog home.

He debated how to answer. Did he even need to? No, because he was going to go, and Cafferty knew he would. He would go because he was curious – curious about all sorts of things. He would go because they had history.

On the other hand, he didn’t want to look too keen. So instead he slipped his mask on, walked to the bar and ordered another pint.

Cafferty’s home was a three-storey penthouse in a glass tower on a development known as Quartermile. It had been the site of Edinburgh’s old infirmary, and the original renovated buildings nestled between steel-and-glass newcomers. Rebus’s own home was a ground-floor tenement flat on a quiet street in Marchmont, only a ten-minute walk away. The two were separated by Melville Drive. On Rebus’s side sat Bruntsfield Links, where pitch-and-putt was played in summer months. On Cafferty’s side sat a large grassy area known as the Meadows. There were usually plenty of joggers, cyclists and dog-walkers making use of the space. Rebus had to avoid a few as he walked towards Quartermile. He wondered if Cafferty was watching his approach. On the off chance, he offered a two-fingered salute in the building’s general direction, earning him a quizzical look from a young couple seated on a nearby bench.

He paused for a moment outside the door to Cafferty’s building, wishing he still smoked. A cigarette would have given him a reason­able excuse to delay entering. Instead of which, he pressed the buzzer. The door clicked open, the lift taking him up eight storeys to the top. The landing here led to just the one door. It had already been opened. A well-built young man was scooping up the mail that had obviously been pushed through the letter box earlier. He was fair-haired and had a build toned by regular visits to the gym. He sported what looked like a Fitbit on his left wrist. No actual watch and no rings.

‘Who are you then?’ Rebus enquired.

‘Mr Cafferty’s personal assistant.’

‘Must be some job that, wiping his arse as and when. I know the way.’ Rebus snatched the mail from the man’s hand. He’d taken no more than two steps down the hall when a strong grip on his shoulder pulled him up.

‘Need to pat you down.’

‘You’re joking, aren’t you?’ But it was clear from the look on the young man’s face that he wasn’t. Rebus managed a sigh as he unzipped his padded jacket. ‘You know I was invited here, right? Making me a guest rather than a really shite ninja?’