Sergius, a student in Paris, is called upon to ascend the throne of Deliria, and the Duke of Onnandoff comes to announce the fact accompanied by his beautiful young Duchess. The Prince, however, has gone off for a night's merrymaking in Paris, and at a popular cafe he meets and falls in love with a beautiful ex-dancer, who is none other than the Duchess of Onnandoff, who is paying a surreptitious visit to the scene of her former triumphs. A group of conspirators who wish to prevent Sergius ascending the throne, lure him to the house of the Delirian Ambassador where they intend to keep him prisoner. The young Duchess caught in a heavy shower, is given shelter at the house by the Ambassador's footman. Here she learns of the plot against the youth with whom she has spent a charming evening, and it is her wit and ingenuity that upset the plans of the conspirators and enable Sergius to secure his crown.