Piet Hoffmann is the best undercover operative in the Swedish police force, but only one other man is even aware of his existence. When a drug deal he is involved in goes badly wrong, he must face the hardest mission of his life - infiltrating Sweden’s most infamous maximum-security prison. Detective Inspector Ewert Grens is charged with investigating the drug-related killing. Unaware of Hoffman’s real identity, he believes himself to be on the trail of a dangerous psychopath. But he cannot escape the feeling that vital information pertaining to the case has been withheld or manipulated. Hoffmann has his insurance - wiretap recordings that implicate some of Sweden’s most prominent politicians in a corrupt conspiracy. But in Ewert Grens they might just have found the perfect weapon to eliminate him.