Officer Wilson of the U.N. Commission against war crimes (Edward G. Robinson) is searching for a Nazi criminal, Franz Kindler (Orson Welles) who now lives undercover, with another identity. Kindler’s assistant, Konrad Melnike, is released in order to follow his steps towards the Nazi and as a matter of fact, Konrad goes to Mexico. After getting his tracks lost, he meets Franz, but gets killed by him. His new identity is Professor Charles Rankin, married to Mary, and during a dinner party also attended by Officer Wilson, Franz betrays himself about Karl Marx’s origins. At this point the famous epilogue will take place on a tower where an enormous clock will be the main character for the end of the Nazi criminal. The film was a discreet success for RKO and it also was Welles’ third and last film with the company, according to the contract.