Midnight. Stockholm is in motion – then everything changes. A series of spectacular deeds paralyze the city, the whole community. The police management are convinced that they can stop new acts of madness, but criminal inspector Mariana Hermansson can sense that something is not right.

While Mariana’s bosses are lead astray, her search leads her to ward 5 at a forensic psychiatry clinic. Someone has been planning crimes no one has ever seen before, crimes beyond the imaginable. There is only one way that she can solve them: she has to get to the other side of the walls and barbed wire. By her side are the police force’s foremost infiltrator, detective Ewert Grens, and the criminal Piet Hoffman. This will be their final joint adventure.