Filmed on location in Copenhagen, Hidden Fear stars John Payne as an American lawman whose Denmark-based sister Natalie Norwick is in big, big, trouble. Arrested for the murder of her music hall partner, Natalie hopes that Payne can clear her name. Following the evidence trail, the detective meets the murder victim's girlfriend Anne Neyland, who in turn leads our hero to a vicious counterfeiting gang, headed by ex-Nazi Alexander Knox. Conrad Nagel, who evidently went along for the ride to get a free vacation, appears briefly as Neyland's American sugar daddy. Given only a limited release, Hidden Fear hid from view until it was picked up for an ABC network telecast in 1963.