Summoned in the early hours of the morning to a Glasgow flat, forensic scientist Rhona MacLeod is confronted by a horrific crime scene. A teenage boy has been found mutilated and strangled to death by a vicious killer. But her grim task of scanning for evidence is made even more unsettling than normal by the boy’s remarkable resemblance to her – and by the fact that she gave up a baby boy for adoption 17 years ago. Overcome by guilt, Rhona sets out to find the boy’s killer and establish whether the young victim is her long-lost son.

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.

When a woman's body is discovered in a cathedral and hours later a young man is found hanging from a tree outside his home, Detective Lottie Parker is called in to lead the investigation. Both bodies have the same distinctive tattoo clumsily inscribed on their legs. It's clear the pair are connected, but how? The trail leads Lottie to St Angela's, a former children's home, with a dark connection to her own family history. Suddenly the case just got personal.

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 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.