Storyline: Five years after a traumatic incident, Detective Harry Hole buries himself in case work when a weapons seizure points to a shocking suspect.

Storyline: As a gruesome and perplexing murder strikes Oslo, a personal tragedy drags Harry back into bad habits and an obsessive search for answers.

Storyline: After crossing one line too many, Harry is reassigned to a missing persons case that raises his suspicions. Waaler sets a trap with lethal consequences.

Storyline: The police must call on Harry's expertise after a chilling package arrives by post. But with Waaler leading the case, his return comes at a price.

Storyline: With evidence suggesting they're dealing with a serial killer, the police shift tactics and chase a promising lead as gang violence escalates across Oslo.

Storyline: Unable to find a logical connection between the symbolism, locations and victims, Harry attempts a mind-bending method to crack the serial killer's code.

Storyline: Patterns and riddles point Harry in the direction of the next possible murder. But is he finally one step ahead, or still chasing the killer's tail?

Storyline: Hunted by his own, Harry goes underground with his captive to prove a theory - only to uncover another deceptive layer separating him from the truth.

Storyline: Harry closes in on the secret behind the murders, but as his worst fears surface, the cost of his relentless pursuit of justice becomes alarmingly clear.