When a landslip on Pembrokeshire’s stunning coastal path reveals the harrowing remains of two bodies, ex-DCI Evan Warlow’s quiet retirement is shattered.

Detective Chief Inspector Harry Grimm is forced to take leave from Bristol’s Major Investigations Team when his boss, tired of Harry chasing the ghost of his murderous father, sends him north on secondment. Used to city life and high stress, Harry fears his life will now be spent handing out speeding tickets, finding lost sheep, and directing tourists. But when a local teenager runs away, Harry finds himself pulled into an investigation much worse than anyone could have ever expected.

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.

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.

DS Whitney Walker wants a promotion, but it’s hard when she’s trying to balance motherhood with a career. When a newborn baby is kidnapped from the local hospital, she draws on her skills as a mother to help. Despite being ordered not to, and when the leads are going nowhere, Walker enlists the help of a local journalist who’s convinced it’s the work of an international baby smuggling ring. Walker’s plan backfires and she fears they’re running out of time.