This adventure-filled drama finds Englishman Rudolf Rassendyll (Ronald Colman) on vacation in a small European country, where he discovers his resemblance to the nation's royal heir-apparent, Rudolf V. When the king-to-be is drugged and incapacitated, Rassendyll must impersonate him, so that the scheming Duke Michael (Raymond Massey) can't assume the throne. To further complicate matters, Rassendyll starts to fall for Rudolf V's intended bride, Flavia (Madeleine Carroll).