Ronald Colman stars in David O. Selznick's classic production of Anthony Hope's swashbuckling adventure. The film takes place in a mythical Central European kingdom with Colman in a dual role as King Rudolf V and Rudolph Rassendyl, a visitor from England who's a distant cousin to the prince. Arriving in the city of Strelsau, the inhabitants are startled by Rudolph's resemblance to the prince. Spotted by two of the prince's aides, Captain Fritz von Tarlenheim (David Niven) and Colonel Zapt (C. Aubrey Smith), the Englishman is taken to meet the prince at his hunting lodge. The two lookalikes have dinner together as the prince tells Rudolph of the preparations for his upcoming coronation as king. The next morning, Zapt wakes Rudolph and informs him the prince had been drugged the night before and is now in a coma. Because of their similar appearance, Zapt prevails upon Rudolph to impersonate the prince at the coronation, otherwise the prince's evil brother Black Michael (Raymond Massey) will be crowned in his place. With the assistant of Zapt and von Tarlenheim, Rudolph bluffs his way through the coronation, successfully fooling Michael, who is shocked to see his brother alive. Crowned king, Rudolph then meets Princess Flavia (Madeleine Carroll), the prince's fiancee. As they proceed to the reception, Princess Flavia is amazed how kindly the prince is now treating her. Rudolph is falling in love with her, but Michael suspects something foul and dispatches Rupert of Hentzau (Douglas Fairbanks Jr.) to investigate the matter further, preparing to gain control of the throne at any cost.