A violent rapist is attacking women, leaving them for dead on south London streets. When young policewoman Maeve Kerrigan responds to a domestic disturbance, she's horrified to stumble across the latest victim. But as a new recruit - and a female to boot - she'll have to face down not only her own nerves but rampant sexism from her colleagues if she wants to be taken seriously enough to even assist on the case.

As an undercover police officer, Rob Langton is used to terrifying situations. But his new assignment is the most dangerous yet – to infiltrate the notorious Carter family, and bring its patriarch Geraint to justice. After gaining Geraint’s trust, Rob finds himself becoming the criminal's right-hand man. The deeper Rob gets, the more danger he’s in. Then Geraint’s horrific plan comes to light – a bomb in a public place, designed to stir up anti-immigrant sentiment. Rob is the only person who can stop the carnage, but time is running out.

The story opens with the apparently accidental drowning of a sixth form student in the Norfolk countryside. As a matter of routine, or so it seems, the case passes across the desk of Detective Sergeant Smith, recently returned to work after an internal investigation into another case that has led to tensions between officers at Kings Lake police headquarters. As an ex-DCI, Smith could have retired by now, and it is clear that some of his superiors wish that he would do so.

On the day she returns to active duty with the Serial Crimes Unit, Detective Inspector Anjelica Henley is called to a crime scene. Dismembered body parts from two victims have been found by the river. The modus operandi bears a striking resemblance to Peter Olivier, the notorious Jigsaw Killer, who has spent the past two years behind bars. When he learns that someone is co-opting his grisly signature - the arrangement of victims’ limbs in puzzle-piece shapes - he decides to take matters into his own hands.

Cal Hooper thought a fixer-upper in a bucolic Irish village would be the perfect escape. After 25 years in the Chicago police force and a bruising divorce, he just wants to build a new life in a pretty spot with a good pub where nothing much happens. But when a local kid whose brother has gone missing arm-twists him into investigating, Cal uncovers layers of darkness beneath his picturesque retreat, and starts to realize that even small towns shelter dangerous secrets.