A kingdom's ascending heir, marked for assassination, switches identities with a lookalike, who takes his place at the coronation. When the real king is kidnapped, his followers try to find him, while the stand-in falls in love with the king's intended bride, the beautiful Princess Flavia.
| Actor | Role |
|---|---|
 Stewart GrangerRudolf Rassendyll / King Rudolf V | Rudolf Rassendyll / King Rudolf V |
 Deborah KerrPrincess Flavia | Princess Flavia |
 James MasonRupert of Hentzau | Rupert of Hentzau |
 Louis CalhernCol. Zapt | Col. Zapt |
 Jane GreerAntoinette de Mauban | Antoinette de Mauban |
 Lewis StoneThe Cardinal | The Cardinal |
 Robert DouglasMichael, Duke of Strelsau | Michael, Duke of Strelsau |
 Robert CooteFritz von Tarlenheim | Fritz von Tarlenheim |
 Peter BroccoJohann | Johann |
 Francis PierlotJosef | Josef |
 Jay AdlerNot listed | Not listed |
 Kathleen FreemanNot listed | Not listed |
 John GoldsworthyNot listed | Not listed |
 Thomas Browne HenryNot listed | Not listed |
 Doris LloydNot listed | Not listed |
 Stanley LoganNot listed | Not listed |
| SStephen RobertsNot listed | Not listed |
| BBud WolfeNot listed | Not listed |