As Detective Dan Lockhart is called to a wealthy London street to investigate Natasha’s death, he’s startled by the similarity to a previous case. Noticing the cable-tie restraints and the tiny scratches on Natasha’s wedding finger, Dan already knows what he will find if he looks in her mouth - the metal ball which choked her to death. Months earlier, Kim Hardy was found in the same position in a run-down hotel across the city - an identical silver ball in her throat. But Kim’s murderer was caught and sent to prison - did they arrest the wrong man?

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?

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.

It’s been five years since Detective Zac Boateng’s daughter was murdered, and her killer was never found. Now Zac is back working for the Metropolitan Police and is more determined than ever to bring the city’s killers to justice. When a man is found brutally murdered in a rundown south London shop, all fingers point to the highly intelligent and manipulative Darian Wallace. Two years ago, the victim helped send him to prison. And he’s just been released.

There's a serial killer targeting the streets of Newcastle, seemingly picking his victims at random but subjecting them all to the same torturous end. When the Chief Inspector on the case goes missing, it falls on DCI Ryan to track down the man who is brutally murdering women and goading the police to 'catch me if you can'. As everyone becomes a suspect, Ryan and his team get drawn further and further into the case, but for Ryan the nightmare gets closer to home than he could ever have imagined.