When Ryan Kennedy is imprisoned after killing a police officer, he knows what he has to do. Keep his mouth shut about who he was working for, keep his head down, and rely on his youth to keep his sentence short. When he gets out, he'll be looked after. Following the death in the line of duty of a fellow detective, DI Sarah Collins has left the capital for a quieter life in the countryside. But when a missing teenager turns up on her patch, she finds herself drawn into a much bigger investigation—one that leads her right back to London, back to the Met, and back to Ryan Kennedy.

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.

When Matt Ballard was starting out his career, three boys were murdered in the same area, the remote and bleak Gibbet Fen. When the main suspect was killed in a hit-and-run, the killings stopped. But Matt was not satisfied that the real murderer had been caught. Over 25 years later, Matt gets a photo in an unmarked envelope. It's of the Gibbet Fen crime scene. And the picture was taken before the murder took place. More photos arrive, relating to the historic murders, as well as intimate pictures of Matt's very secret private life.

Detective Sergeant Chris Waters got the call at 05.29 that July morning. This is it, said DCI Reeve, you'll be first there, it's all yours, you're the crime scene manager. Suddenly, after months of waiting and wondering, Waters finds himself in at the deep end, and alone at the scene of a puzzling murder. As the investigation proceeds, the detectives at Kings Lake Central find themselves visiting familiar places and talking to some familiar faces, while old enmities reappear in the incident room. Before this is over, Chris Waters will need to make a career-changing decision.

Starting a new life in Snowdonia was always DI Ruth Hunter's dream. Until a twisted killer turned it into her worst nightmare. Detective Inspector Ruth Hunter lives with the pain of her partner’s mysterious and unsolved disappearance. About to hit 50, the veteran police officer trades in the crime-ridden streets of London for a more peaceful life in rural North Wales. But Ruth has barely settled into her new position in North Wales Police, when the body of a brutally murdered woman is discovered...with strange symbols carved into her skin.