Double bill of crime dramas. In 'Operation Diplomat' (1953) Dr. Mark Fenton (Guy Rolfe) has to perform surgery on a secretive patient. When a secretary is killed for disclosing the patient's identity, the situation becomes even more complicated. But will the mystery be uncovered when the police are reluctant to believe Dr. Fenton's story? In 'The Silicians' (1963) a mob leader decides to come clean and subsequently gives evidence against the rest of the Mafia, who get their revenge by capturing his son. It is up to a member of the American Embassy in London to work with Scotland Yard and the French authorities to solve the case.