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.

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.

Haunted by his inability to track down and save his missing wife, DCI Robert Kett leaves the Metropolitan Police behind and moves to Norwich with his three young children, hoping to heal their broken family. But his newfound peace doesn’t last. Two newspaper delivery girls have gone missing in the city, and the clues point to a serial kidnapper. Kett is dragged into the centre of one of the darkest cases of his career - a case that pits him head-to-head against a horrifying evil.

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.