A special unit “Q” of the Copenhagen police was created to investigate high-profile but still unsolved criminal crimes. The head of the unit, Carl Mørck, receives a dossier concerning a brutal murder of a brother and sister committed many years ago. The police officers who had handled the case assumed the killer had to be found among the young inmates of an intermarriage school—offspring of wealthy families. Ten years later, one of the suspects gave a confession and was convicted. It seemed the case was closed. So why did a folder with his materials end up on Carl Mørck’s desk? Who put it there? Who can’t let go of the old tragedy?
Together with his assistant, Carl reopens the investigation, and the former suspects come out of the shadows. There are four of them: Kimmy, who is mentally unwell and lives on the streets of Copenhagen, and three of her former school friends—now extremely influential people. Kimmy plays her own game: she knows a lot and is ready to take revenge.