Duke of Sipoo is a comedy about corruption and family man, Pasi Kovalainen, who has built his empire mostly by questionable means. Kovalainen himself doesn't think he's a criminal, but a average man trying to make a living and a victim of bureaucracy. Prosecutor takes interests in his actions and puts two criminal investigators to investigate everything he does, planning to catch him even for something small and get him put behind bars. At the same time, one reporter and group of other people want his head on a plate too.
