In the shadow of the Pentland Hills, a man has been callously struck down in front of his home. Tyre marks suggest it was no accidental hit-and-run. Somebody wanted him dead and as the man fights for every breath, they might still get their wish. Grappling with the demons he thought he could leave behind after months away on enforced leave, D.S. Malkie McCulloch resists pressure from his superiors to pass the case on to the road policing unit, convinced that whoever was behind the wheel will be waiting for the chance to finish the job.

Detective Sergeant Chris Waters got the call at 05.29 that July morning. This is it, said DCI Reeve, you'll be first there, it's all yours, you're the crime scene manager. Suddenly, after months of waiting and wondering, Waters finds himself in at the deep end, and alone at the scene of a puzzling murder. As the investigation proceeds, the detectives at Kings Lake Central find themselves visiting familiar places and talking to some familiar faces, while old enmities reappear in the incident room. Before this is over, Chris Waters will need to make a career-changing decision.

Five years ago, DCI John Lomond led the search for notorious Glasgow child-killer ‘The Sandman', until personal tragedy forced him off the case. In Lomond's absence, the killer was never found. Now, with nothing but work left in his life, Lomond remains obsessed with the case–despite the nightmares it brings. When a child is abducted in similar Sandman fashion from an affluent Glasgow suburb, Lomond is brought in to find them before it's too late.

When the chief suspect in the notorious Peek-a-boo cop killer case blew himself up, almost taking lead investigator DCI Duncan Bone with him, the psychologically damaged detective thought his days on the force were over. But when another PC is abducted and murdered in the same deranged Peek-a-boo fashion, Bone is persuaded to return to lead the new investigation. But as Bone and his team hunt a copycat killer, and with time running out before yet another cop is slain, Bone’s terrifying past returns to tear open old wounds and push him to very edge of the abyss.

Criminologist Martin Knight lives a gilded life and is a thorn in the side of the police. But then his wife, Liz, goes missing. There is no good explanation and no sign of Martin.... To make things worse, Liz is the ex-girlfriend of DCI Craig Gillard who is drawn into the investigation. Is it just a missing person or something worse? And what relevance do the events around the shocking Girl F case, so taken up by Knight, have to do with the present? The truth is darker than you could ever have imagined.