Frustrated by a seemingly infallible gang of jewel thieves, Scotland Yard arranges to have an undercover agent become part of the gang. Once inside, the agent starts to become attached to a Russian woman who is part of the gang but seems to want to break free of the sordid life she leads. Trying to trap the leader of the gang -- whom no one has ever seen - the police plan goes awry and their agent is put into mortal danger, with his one chance being the Russian woman having told the truth about wanting to break free.
Director: Ralph Ince
Stars: Esmond Knight, Lilli Palmer, Cecil Parker