The Swedish National Crime Unit receives a video of a young woman in her home, clearly unaware she's being watched. Soon after the tape is received, the woman's body is found horrifically mutilated. With the arrival of the next, similar video, the police understand the killer is toying with them, warning of a new victim, knowing there's nothing they can do. Detective Margot Silverman is put in charge of the investigation and soon asks Detective Joona Linna for help. Linna, in turn, recruits Erik Maria Bark, the hypnotist and expert in trauma, with whom Linna's worked before. 

All across Europe, the most ruthless criminals are suffering gruesome deaths. At first, it seems coincidental that their underworld affiliations are finally catching up to them. But when two of the victims are found to have disturbing connections to Detective Joona Linna, it becomes clear that there’s a single killer at work. Still, police are reluctant to launch an investigation. If a mysterious vigilante is making their jobs easier, why stand in his way?

Sixteen-year-old Jenny is abducted in broad daylight and taken to a dilapidated, isolated house where she is chained and caged along with several other girls. Their captor is unpredictable, and as wily as he is cruel: he foils every one of their desperate attempts to escape...and once caught, they rarely survive their punishment. Five years later, Jenny is found dead in a public park, and the police are scrambling to find a lead among the scant evidence. But Detective Joona Linna realizes that this murder has an eerie connection to a death that was declared a suicide years before. 

Late one night, outside Stockholm, Mikael Kohler-Frost is found wandering. Thirteen years earlier he went missing along with his younger sister. They were long thought to have been victims of Sweden's most notorious serial killer, Jurek Walter, now serving a life sentence in a maximum security psychiatric hospital. Now Mikael tells the police that his sister is still alive and being held by someone he knows only as the Sandman.

Detective Joona Linna is on leave dealing with personal and professional issues when he gets pulled into the investigation of a horrific murder at a home for wayward teenage girls. One girl is dead, and another is missing. The local police want to close the case quickly, especially after they discover a bloody hammer under the missing girl's bed. But a woman claiming to see visions of the murdered girl insists there is more going on than meets the eye, and Joona is inclined to believe her. As he digs deeper into the case, he finds himself in dark and dangerous territory.  

A gruesome triple homicide. There’s only one surviving witness - the boy whose family was killed before his eyes...and he can’t remember what happened. The police are desperate for information. Detective Joona Linna enlists the help of hypnotist Erik Maria Bark. But when Bark unlocks the secrets in the boy’s memory, he triggers a terrifying chain of events that will put all their lives in jeopardy. 

Detective Carl Morck has received a bottle that holds an old and decayed message written in blood. It's a cry for help from two young brothers, tied and bound in a boathouse by the sea. After floating in the ocean for years before turning up, the bottle sat forgotten, unopened, on a police department windowsill, before the seal was cracked and the gruesome message, written in Danish, was analyzed. Could it be real? Who are these boys, and why weren't they reported missing? Could they possibly still be alive?

Carl Mørck used to be one of Denmark’s best homicide detectives. Then a hail of bullets destroyed the lives of two fellow cops, and Carl - who didn’t draw his weapon - blames himself. So a promotion is the last thing he expects. But Department Q is a department of one, and Carl’s got only a stack of cold cases for company. His colleagues snicker, but Carl may have the last laugh, because one file keeps nagging at him: A liberal politician vanished five years earlier and is presumed dead. But she isn’t dead...yet.

Harry Hole, drunkard, loner and brilliant detective is reassigned to surveillance after a high profile mistake. He’s bored by his new job until a report of a rare and unusual gun being fired sparks his interest because of its possible links to Neo Nazi activity. Then a former soldier is found with his throat cut. Next Harry’s former partner is murdered. Why had she been trying to reach Harry on the night her head was smashed in?

Una knows she is struggling to deal with her father's sudden, tragic suicide. She spends her nights drinking alone in Reykjavik, stricken with thoughts that she might one day follow in his footsteps. So when she sees an advert seeking a teacher for two girls in the tiny village of Skálar - population of 10 - on the storm-battered north coast of the island, she sees it as a chance to escape. But once she arrives, Una quickly realises nothing in city life has prepared her for this. The villagers are unfriendly. The weather is bleak.