In a Copenhagen park the body of an elderly woman is discovered. Though the case bears a striking resemblance to another unsolved homicide from over a decade ago, the police cannot find any connection between the two victims. Across town a group of young women are being hunted down. The attacks seem random, but could these brutal acts of violence be related? Detective Carl Mørck of Department Q is charged with solving the mystery.
Back at headquarters, Carl and his team are under pressure to deliver results: failure to meet his superiors' expectations will mean the end of Department Q. Solving the case, however, is not their only concern. After a breakdown, their colleague Rose is struggling to deal with the ghosts of her past - a past seemingly connected to one of the division's most sinister case-files. It is up to Carl, Assad and Gordon to unearth the dark and violent truth plaguing Rose before it is too late.