Nils Dickman is a snow plow driver in the town of Tyos, Norway, just elected citizen of the year. His life, however, is shattered by the death of his son Ingvar, found dead by overdose of heroin. The police do not investigate the story but Dickman is sure that his son wasn't a drug user. When he's about to kill himself he learns from Finn, his son's friend, that Ingvar was mistakenly killed by a gang of drug dealers who actually intended to kill Finn. So Nils begins his hunt for his son's murderers.