DI Jack Knox is called in to investigate a high-profile case. A local distiller’s daughter has gone missing, and when he receives a ransom note, his fears that it is a kidnapping are confirmed. Knox decides to take a serious risk to capture the abductors, but the stakes could not be higher. The father is wealthy and well-connected. If Knox’s gamble goes wrong, he’ll have hell to pay. Meanwhile in the prequel story, 'Labyrinth', the body of an attractive young woman is found in woodland on Edinburgh’s iconic Calton Hill.

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 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.

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.

Still grieving from the tragic death of her colleague, DCI Emma Gardner continues to blame herself and is struggling to focus. So, when she is seconded to the wilds of Yorkshire, Emma hopes she’ll be able to get her mind back on the job, doing what she does best - putting killers behind bars. But when she is immediately thrown into another violent murder, Emma has no time to rest. Desperate to get answers and find the killer, Emma needs all the help she can. But her new partner, DI Paul Riddick, has demons and issues of his own.

A woman is found in a local cemetery, crushed to death under a gravestone. A production company is there, filming the remake of a classic sci-fi TV show on the grounds, making the investigation more difficult for DCI Harry McNeil. It's his first day in charge of the cold case unit in Edinburgh. After spending four years in Professional Standards, he has little choice but to take the promotion.

Mark Campbell is in trouble. His latest book is five years late and his recent divorce has cleaned him out. Worse, his debts with Vic Hebden aren’t the kind you consolidate into one easy payment. And he’s already missed three. But Mark has a plan—finish his novel, then pay Hebden off with the advance. His daughter, Kay, is spending her summer holiday in the far north of Scotland. The hotel calls—Kay has run off, leaving a big bill, her phone, and a copy of Mark’s last book, Break the Chain. There's only one person to turn to—his ex, Olivia. Kay’s stepmother.

Ailsa Connolly was a brilliant psychologist and a respected criminologist. She was also a serial killer. Six years ago, DCI Sean Bracken caught her just before he was about to become her seventh victim. Every year on the anniversary of her incarceration, she taunts him with a phone call, giving him one message: "When I get out, I'll kill you." Now, Bracken has transferred back to Edinburgh and is thrown into the deep end on his first day back on duty. There's a killer who is emulating Ailsa, threatening to surpass her body count. 

Detective Lauren Pengelly has only been part of the Penzance police force for less than two years, but that’s enough time to know that the sleepy Cornish town doesn’t see many murders. So, when the bones of a woman with a hole in her skull are discovered behind a derelict cottage, she immediately assumes the worst. Rallying her team, Lauren is flooded with a strange sense of relief when the bones turn out to be almost twenty years old, not a recent victim. But it quickly turns to dread when she receives her second heart-stopping call of the day–a little girl, Isla, has been kidnapped.