A convert is a person who agrees to cooperate with an enemy in exchange for some benefits. It can be a criminal who cooperates with the police or a policeman who delivers secrets to mobsters. No matter if the convert is the guardian of public order or the bandit it is always perilous game where a life is at stake. Main characters of Converts are Paul Sikora, an experienced officer of Central Investigation Bureau and Blacha - John Blachowski, a mobster from the most powerful gang in Poland. The axis of the series is complicated high risk game which is played between these two protagonists. The policeman tries to convert the criminal and the criminal attempts to corrupt the officer. These two men live on the opposite sides of the barricade, however, they have many things in common.