In post-war France, Jan Bojarski, a young Polish refugee, becomes the greatest counterfeiter of all time. For more than fifteen years, he leads a double life, making counterfeits in a garden shed that are "truer" than the bills issued by the Banque de France. All these years, he manages to avoid being caught by the police - until his arrest becomes the main goal of Commissaire Mattei in a hunt that turns into a duel.