A series of violent murders paralyze Stockholm. Private investigator Fredrika Bergman and her colleagues seek out to solve these crimes, but soon their existence is put under threat.

Romanian Lidia is lured to Sweden, where she is locked up and prostituted. In her search for revenge, her fate is intertwined with the police officer Ewert Gren, who chases a dangerous criminal.

Sonja lives a rather carefree life with her beloved family. The husband Frederick's marijuana business providing family finances a silver lining. But life is shattered and Sonja forced to play a dangerous game with both organized crime and police to protect their children. She can no longer be sure which ones are her friends and who she can trust.

When Johan Falk was 19 years old he lost his girlfriend Maria and their unborn child when Maria got hit by a car. Falk takes the accident very hard and do not even go to the funeral. He decides that crime must be fought and applies immediately to the Police Academy. The movies are, however, only about Falk as an police officer with many years of experience from the National Task Force. He often goes his own way and does not shy away from using controversial methods. This leads to that the colleagues often experience difficulties in cooperating with him and managers are forced to turn a blind eye to what he's doing.