DS McNab was a hero of Chrissy’s, having shielded her pregnant self from a gunshot, the scar of which he still wore on his back, although it was now cleverly disguised by a skull tattoo.

‘What? No rolls?’

Rhona looked about in the hope that the familiar paper bag might be on view, just not yet opened to allow the hot aroma to escape.

‘I thought we’d try something new for breakfast for a change,’ Chrissy said, rather sheepishly, it seemed to Rhona.

‘What exactly?’ Rhona demanded.

‘Porridge pots,’ Chrissy offered. ‘And you have a wide choice of flavours.’ She pointed at a line of the pots. ‘Cinnamon, apple, banana, honey, syrup. All very healthy,’ she added.

‘What’s going on, Chrissy? Since when have you been health-conscious?’

Her forensic assistant looked mightily offended by that remark. ‘Since I had wee Michael.’

‘I’m talking about your eating habits, not what you feed your son.’

Chrissy shrugged. ‘People change. They get older. They get wiser.’

‘You’ve joined a gym,’ Rhona accused her.

‘Never,’ Chrissy replied with gusto.

‘What then?’

There was a moment’s silence before Chrissy admitted, ‘I’ve taken up running.’

‘Really?’

Rhona was impressed if it were true, although Chrissy had ‘taken up’ things before now, only to discover her enthusiasm waning after a while. Usually because the guy she was joining on such pursuits had lost his appeal.

‘Who is it?’ Rhona demanded.

‘No one,’ Chrissy said categorically. ‘Just me. So, what’s your poison?’ She gestured at the line of pots.

Trying not to look too downhearted, Rhona chose a pot, hoping this new plan of how to start the day was simply another one of Chrissy’s fanciful ideas, like changing her hair colour regularly, and would soon be abandoned.

‘Right,’ Chrissy said, pouring what Rhona prayed was still strong coffee. ‘There’s a message for you from Bill. He wants you to call him after breakfast.’

DI Wilson, or Bill as she and Chrissy called him, had been Rhona’s mentor since she began in this job. He’d been on duty the night she’d attended the scene of a particularly brutal murder of a teenage boy – a boy who had looked so like her that Rhona had imagined he might be Liam, the son she’d given up for adoption seventeen years previously. In the end, Liam had found her and they’d eventually come to an understanding regarding why Rhona, when still a teenager herself, had given up her baby.

She’d confided in Bill back then, how personal the death of that teenager had been to her, and how it had prompted her to search for her own son. Bill, with two teenage children of his own, had known exactly what she meant.

‘It’s my biggest fear,’ he’d said. ‘That one day I’ll turn up at a scene of crime and one of my kids is the victim . . . or the perpetrator.’

His inclusion of perpetrator hadn’t just been a way to lighten the tension of that moment. Every parent worried about their kids getting into trouble, police officers probably more than most. They knew that kids from supportive families could go down the wrong path just like the ones who didn’t have the same advantages.