Jan Bojarski, a young Polish engineer, takes refuge in France during the war. There, he uses his skills to produce forged identity papers during the German occupation. After the war, the lack of official civil status prevents him from filing patents for his many inventions, forcing him into poorly paid odd jobs… until the day a gangster offers him the chance to use his exceptional talents to print counterfeit banknotes. He then begins a double life, unbeknownst to his family. Very quickly, he finds himself in the crosshairs of Inspector Mattei, France’s finest detective.