Detective Chief Inspector Harry Grimm is forced to take leave from Bristol’s Major Investigations Team when his boss, tired of Harry chasing the ghost of his murderous father, sends him north on secondment. Used to city life and high stress, Harry fears his life will now be spent handing out speeding tickets, finding lost sheep, and directing tourists. But when a local teenager runs away, Harry finds himself pulled into an investigation much worse than anyone could have ever expected.

When Victoria Davies was pushed off her stately home's roof in 2001, all evidence pointed to her husband Michael. But now, 20 years later a letter has appeared, written by Victoria before her death; a letter that was never received, and a letter that brings new suspects into the fray; Labor MPs Shaun Donnal, Andrew MacIntyre, and Charles Baker.

In the shadow of the Pentland Hills, a man has been callously struck down in front of his home. Tyre marks suggest it was no accidental hit-and-run. Somebody wanted him dead and as the man fights for every breath, they might still get their wish. Grappling with the demons he thought he could leave behind after months away on enforced leave, D.S. Malkie McCulloch resists pressure from his superiors to pass the case on to the road policing unit, convinced that whoever was behind the wheel will be waiting for the chance to finish the job.

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.

When the chief suspect in the notorious Peek-a-boo 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 Peek-a-boo fashion, Bone is persuaded to return to lead the new investigation. But as Bone and his team hunt a copycat killer, and with time running out before yet another cop is slain, Bone’s terrifying past returns to tear open old wounds and push him to very edge of the abyss.