Adapted from a novel written by Jo Nesbo, the film is centered on Norwegian detective Harry Hole (Michael Fassbender). In a cottage in a snow-covered field, a man in a police car comes to visit a boy and his mother. There, he subjects the boy to a test, hitting his mother every time the boy answers the wrong questions. Things degenerate quickly, and eventually a Volvo sinks into a lake and a child is left homeless.
Nowadays, Harry is an alcoholic who sleeps in the bus station, but even so he remains a great cop, despite his personal problems. Katrine Bratt, who becomes an informal partner in a serial killer case, tells Harry that he studied the cases he worked for when he was in the “academy”. Harry is a brilliant detective, but his private life is a real disaster.
When a person’s body is discovered during the first snowfall of the new winter season, Harry fears that a serial killer whose crime he has investigated in the past may have returned and start the series of murders they consecrated him. With the help of the new brilliant recruiter, Katrina, Harry has to put together the clues and cases of the last decades in the hope that he will unravel the mystery behind these crimes and capture the killer once and for all who haunts his conscience.