William Wisting and his team are hit hard when a crime scene inspection with serial killer Tom Kerr goes horribly wrong. Wisting's daughter Line now has to deal with the consequences of her documentary causing it all.

Wisting tries to gather the team after the tragedy that has befallen them. He is forced to cooperate with Kripos investigator Stiller in the hunt for the mysterious helper.

A new disappearance makes Wisting and Stiller fear that the killers are about to flee the country. But has the new victim really been kidnapped? A new clue causes the police to arrest a suspect.

Line's shocking findings overturn the police's theory of "The Other". The perpetrator gets rid of loose threads and time is running out. Wisting discovers the secret that his daughter has kept hidden from him.

Wisting and his team are warned about a cruel crime scene in Larvik. The severed head of a young asylum seeker is found on a stake in the middle of the square. FBI agent Maggie Griffin returns to assist in the case.

When a corpse appears in the net of a local poacher, the two killings are linked. Line suspects that Wisting has had a relationship with the manager at the care center.

Maggie is forced to share information, which she has previously kept secret from Wisting. The investigation takes a whole new turn, and leads Wisting and Maggie on a new hunt across the border into Sweden.

In Sweden, Wisting and Maggie find a former victim. Together with the Swedish police, they are drawn into a fierce police action, and the final settlement is both intense and surprising.

Six-year-old Clifford Greenwood vanishes from the family hotel Wildenvey and an employee is found dead. Detective William Wisting believes the boy was kidnapped. The Greenwood family is shocked, but Wisting discovers they have secrets.

Clifford's family receives a ransom demand and a cryptic message. The clues suggest Clifford has been taken as a revenge against his grandfather. Wisting's daughter, Line discovers her ex, Tommy, has fallen into very bad company.

Wisting is under pressure, still without leads. Clifford's parents await contact from the kidnapper but receive a mysterious message that leads them to a gruesome discovery. It's clear the kidnapper wants to tell them something, but what?

Wisting is under pressure, still without leads. Clifford's parents await contact from the kidnapper but receive a mysterious message that leads them to a gruesome discovery. It's clear the kidnapper wants to tell them something, but what?

While recovering from a severe injury, Wisting receives an anonymous letter in the mail. The cryptic content leads Wisting to suspect a possible injustice in an old murder case where a 17-year-old girl was killed, and her ex-boyfriend was convicted.

A new anonymous letter leads to fresh evidence, but not everyone is happy to see the old murder case back in the spotlight. Wisting realizes he is being opposed by powerful forces within the police, as he keeps searching for the secret messenger.

A breakthrough in the case takes Wisting to Vilnius for a meeting with Interpol investigator Harriet Dunn. What is meant to be a simple questioning of a suspect becomes far more complex for both of them - both professionally and personally.

New DNA evidence appears to solve the murder of Tone, but Wisting still feels that something is amiss. Wisting and his colleagues must call on all of their skills and experience to avoid a dramatic and dangerous situation.