Darkness: Those Who Kill

Five years ago, Alice Ejbye's 18-year-old son Markus was murdered by a serial killer who was never found. Alice is now seriously ill and asks criminal profiler, Louise Bergstein, the daughter of her best friend, to help solve the case. At the same time, elsewhere on Funen, a man named Peter Vinge receives a fatal message from his wife Masja.

A young man has been found in the woods, tortured and stabbed to death. Profiler Louise Bergstein and the head of the investigation Karina Horup try to find evidence for whether the murder can be attributed to a serial killer who, after a five-year hiatus, may now be active again. They slowly work their way towards the killer's highly unusual motive. Meanwhile, Peter Vinge struggles with being a single parent to his son, Johannes, and looks for his next victim.

Louise Bergstein and Karina Hørup discover that the serial killer has a claimed a new victim, William Fjeldby, who was kidnapped and abducted in his own car. William's father, multimillionaire Gorm Fjeldby, clings to the hope that his son has been kidnapped for a ransom and is therefore still alive. As the police search for William, Peter Vinge tries to celebrate Johannes's birthday without Masja. It dawns on Johannes that his father is hiding something from him.

Alice Ejbye receives some bad news from the doctor. At the same time, despite two new victims, the police have yet to find the man who killed her son Markus. Desperate, Alice posts a video on social media offering a reward which has consequences for her relationship with Louise. The police are inundated with information from people who are after the reward, and Karina and Louise struggle to determine whether there is anything useful among all the information. Peter takes his frustration out on his next victim.

Seven weeks after Alice's death, Louise is in mourning and wants to go home as Karina issues her with an ultimatum regarding the case. Alice's death raises a new suspicion which takes the investigation in a new direction. Peter Vinge focuses on his work at a local sawmill, where he receives an unexpected offer from Leif. At the same time, Peter is in conflict with Johannes who remains in a stage of teenage revolt against his father.

Louise Bergstein continues to assist the investigation to find the serial killer, who now has six brutal murders to his name. With Karina Hørup, Louise returns to the first victims in an attempt to find out where they may have met their killer. Peter notices that the police are closer to him than ever before, and at the same time happens to meet Louise again.

Unaware of who he really is, Louise gets far too close to Peter. But the terrible truth lurks beneath the surface. Karina tries to find new evidence for the investigation on her own, and an earlier clue resurfaces, moving the case forward. Peter sorts his life out and gives Johannes a message that his son has a hard time coming to terms with.

The police take Johannes to the station, and Louise fears that the truth about her and Peter Vinge will be revealed. Meanwhile, Peter meets his ex-wife Masja, who has returned from Singapore without notice in order to set things straight. Karina, Søren and Torben desperately try to find Peter before he can claim another victim.