She always thought she’d have daughters. There was no rational basis to believe this would be the case; it was simply how she had imagined motherhood, probably influenced by her own upbringing. She’d have little girls who liked scrapbooks and horses and dressing up; she’d read them Malory Towers and Heidi, and tell them about the games she liked to play when she was a girl. Instead she’d got two boys and was utterly outnumbered in her own home, the only female. No scrapbooks, no horses, just guns and swords, fake wounds and plastic dog turds. Instead of Malory Towers and Heidi, she was reading Mr Gum and Captain Underpants, and instead of her telling them about innocent childhood days on a farm, they were asking about dead bodies and whodunits.

That said, she’d be more comfortable telling them about the smelly corpses than about ‘solving’ the murders. Guts and gore they were fine hearing about, as evidenced by the Horrible History books lining their shelves, but the squalidly mundane realities framing the deaths were another matter. The Putrid Present was maybe a bit much for wee boys to cope with.

The very word ‘whodunit’ put her in mind of her one-time boss and mentor, Moira Clark, whose mantra – often restated bearing the added emphasis of a clout to the back of the head with a file folder – was simply: ‘This is Glesca.’

The first time Catherine heard it was in direct response to her suggestion that a case was ‘starting to look like a whodunit’.

‘This is Glesca,’ Moira told her. ‘Any time you’re confused, take a wee minute to remind yourself of that inescapable fact: this is Glesca. We don’t do subtle, we don’t do nuanced, we don’t do conspiracy. We do pish-heid bampot bludgeoning his girlfriend to death in a fit of paranoid rage induced by forty-eight hours straight on the batter. We do coked-up neds jumping on a guy’s heid outside a nightclub because he looked at them funny. We do drug-dealing gangster rockets shooting other drug-dealing gangster rockets as comeback for something almost identical a fortnight ago. We do bam-on-bam. We do tit-for-tat, score-settling, feuds, jealousy, petty revenge. We do straightforward. We do obvious. We do cannaemisswhodunit. When you hear hoofbeats on Sauchiehall Street, it’s gaunny be a horse, no’ a zebra, because?’

‘This is Glesca,’ she answered.

Catherine was still closing the car door as Laura pulled away, never mind waiting for her to clunk-click. The girl was keen, give her that, but the guy would still be dead when they got there.

‘What are we dragging you away from?’ Laura asked. ‘A night in front of the telly? Dinner for two and a bottle of wine with the kids tucked up?’

‘Laura, it’s ten past three.’

‘Christ. Sorry.’

‘Been there.’