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.

In the remote forests of Stillwater, Minnesota, you can scream for days and no one will hear you. So when the bodies of two 15-year-old girls are discovered frozen in the snow, Special Agent Nikki Hunt is sure the killer is local: Someone knew where to hide the girls and thought they would never be found. Though Nikki hasn’t been home in 20 years, she knows she must take over the case.

There’s a blood moon rising over the tiny Maine town of Coyote Cove when Chief Maggie Riley comes across the body of a man, blood seeping from stab wounds into the damp forest floor. As she desperately struggles to secure the scene as an approaching storm threatens to destroy all evidence, Heather, a local teenage girl, emerges from the woods terrified, a silent scream on her lips.

An eight-year-old girl, Chelsea Compton, is missing in Pine Valley, California, and for Detective Katie Scott it’s a cruel reminder of the friend who disappeared from summer camp 20 years ago. Unable to shake the memories, Katie vows she won’t rest until she discovers what happened to Chelsea. But as Katie starts to investigate, the case reveals itself to be much bigger and more shocking than she feared. Hidden deep in the forest she unearths a makeshift cemetery: a row of graves, each with a brightly colored teddy bear.

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.

Three years ago, DCI Laura Hart was the top hostage and crisis negotiator for the Greater Manchester Police. Then her husband was kidnapped. Despite her best efforts to reason with the criminals, he was brutally murdered. Now living on the Isle of Anglesey in Wales, Laura is slowly healing. Then she gets a call: armed drug dealers have seized a tourist boat—and her 10-year-old son Jake is on board. There’s no other negotiator available, and the police need her to step up.

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.

Lori once lived the perfect life with her husband Howie and their teenage daughter Molly—until the day Howie left for work and vanished without a trace. Haunted by her loss, Lori, a former investigative journalist, retreated from the city to rural isolation to become an author, seeking solace in the company of her beloved dogs. However, Lori's ordered, solitary existence is about to be turned upside down. As Frankie Evans, the man she helped convict for murder, has walked out of prison a free man. And he is intent on finding her.

A brutal double murder on a Norfolk beach horrifies the town of Cromer. The way the victims died is chilling and so Norfolk’s Major Investigation Team task DS Ashley Knight to manage the case. It soon becomes clear that the murders were carefully planned and the finger of suspicion points to an organised crime gang, but as the evidence mounts, a far more sinister theory emerges.