Was the biggest case of his career the worst mistake he ever made? Ten years ago, DCI Jack Logan stopped the serial child-killer dubbed "Mister Whisper", earning himself a commendation, a drinking problem, and a broken marriage in the process...When another child disappears a hundred miles north in the Highlands, Jack is sent to lead the investigation and bring the boy home. But as similarities between the two cases grow, could it be that Jack caught the wrong man all those years ago?

DS Rakesh Siyal is an idealist. Frustrated as an Edinburgh human rights lawyer, he joins the police, determined to solve the problems he sees with the criminal justice system from the inside, rather than out. His first day as a cop sees him sent down to Galashiels in the Scottish Borders, where he’s given a simple task – return a suspect to Glasgow to face justice.

D.I. Duncan McAdam is dispatched home to the Misty Isle. A body has been found buried in a remote location on the Waternish peninsula. Well-preserved in the peat, Isla Matheson—missing for the better part of two decades—is revealed to a shocked island community. A teenage runaway is dead...and no one is talking.

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 "peekaboo 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 peekaboo fashion, Bone is persuaded to return to lead the new investigation.