And she had, many times. It was easy to lose track of normal people’s schedules when you were on a run of shifts. You remained aware that you were out of synch but became vague about by how much, and would take a random stab on the basis of whether it was dark or light. At least it assured Catherine that she wasn’t sporting that conspicuously dragged-out-of-bed look.

Laura, for her part, had an animated eagerness about her that suggested she really needed to cut down on the coffee. She could come across like a probationer as a result, despite being an experienced DI. This girlish keenness was at odds with her dress, too, which seemed sober to the point of austere. Catherine couldn’t decide whether she seemed like a young girl dressing primly to look older or some wild child trying too hard to rein in her natural instincts.

‘Heart-starter that call in the dark, eh?’ Laura stated. ‘You never get used to it.’

‘I was awake anyway. Fraser had a bad dream, and of course as soon as I appeared, Duncan woke up as well. They were giving me a grilling, so I was saved by the bell. I hate it when they ask me about my job. The other night Duncan wanted to know where gangland was. I think he’d seen it on a newsagent’s billboard. I had to stop myself telling him it was a theme park, just to see the look on his face. “Aye, they’ve got the nuttercoaster and the joyriding dodgems, but watch yourself on the shooting gallery, because they shoot back.”’

‘I always thought it sounded like a shop,’ said Laura, accelerating through a set of lights as they turned amber. ‘You know, Gangland: your one-stop for all your criminal needs. What did you tell him?’

‘I told him he couldn’t find it on a map.’

‘Can find it on my sat nav tonight, though. Capletburn Drive, Gallowhaugh. Think it’s a light industrial estate. Appropriate. Nobody lives in gangland: they just work there.’

‘No,’ Catherine disagreed. ‘Plenty of people have to live in gangland. Just none of the gangsters.’

They drove along the dual carriageway, heading east through Shawburn, grim tenements and post-war mid-rises on either side. It all seemed so placid, so still, and at such times Catherine couldn’t help but wonder about the lives that were led behind all those closed curtains.

Laura was glancing left and right with eager curiosity at what flanked her route. She had not long transferred from Lothian and Borders, her command of both the local geography and local colour still in its rudimentary stages.

‘You been to Gallowhaugh before?’ Catherine asked her.

‘No. What’s it like?’

‘You ever come across a place that looks really depressing and run down, then you hear people say it’s a real shame what’s happened to it, because it used to be so much better?’