In Italy in 1939, a European man calling himself Mr. Imperium uses a ruse to meet an attractive American woman, Frederica Brown. He eventually is revealed to be Prince Alexis, an heir to the throne and a widower with a six-year-old son. He nicknames her "Fredda", so she calls him "Al". When his father becomes gravely ill, he must rush to be with him, but asks prime minister Bernand to deliver to Fredda a note of explanation. Bernand instead tells her the prince is gone for good, that this is his usual method of seducing and abandoning women. Twelve years go by. One day in Paris, a cinema's marquee makes it clear that "Fredda Barlo" is now a movie star. Fredda's former love travels to California, where film producer Paul Hunter is now in love with her and proposing marriage. Fredda decides to drive to Palm Springs to think about his proposal, as well as to decide which actor should co-star in her next film, about a girl who falls in love with a king. "Mr. Imperium" takes a room next to hers, and soon they meet and embrace. He explains the crisis that took place at home during the war and prevented him from looking for her. Now he wants a new life, and Fredda believes he could even portray a king in her film. Bernand turns up, however, to say that his son is preparing to ascend to the throne. Mr. Imperium realizes he is needed there, so he must say goodbye to the woman he loves once more.