To avoid publicity upon her return to the United States, Dorothy Hunter, the "richest girl in the world" whom the "world" has never seen, uses her secretary, Sylvia Lockwood, to impersonate her. Just before she is to announce her upcoming marriage, Dorothy's fiancé Donald breaks their engagement, explaining that he has fallen in love with someone else. Devastated by Donald's contention that no man could ever love her for herself, Dorothy enlists Sylvia to pose as her at her engagement party. There, while pretending to be Sylvia, Dorothy meets handsome Tony Travers and plays a game of pool with him. Tony, believing Dorothy to be the secretary, invites her to a canoe ride, but winds up taking Sylvia instead. Furious, Dorothy, with Sylvia's husband Phillip in tow, pursues Tony and Sylvia in a speedboat and causes their canoe to capsize. Although Tony insists that his interest in Sylvia is strictly polite, Dorothy insinuates that if the opportunity to marry the heiress presented itself, he would take it. While maintaining that he prefers Dorothy, Tony accepts the false secretary's challenge to woo "the heiress" and agrees to invest his modest savings in a speculative stock venture in order to finance his courtship. After two weeks of romancing, Dorothy, whose guardian, John Connors, believes that her "love tests" are unfair, advises Tony to propose to Sylvia during a scheduled Adirondack retreat. Buoyed by Dorothy's confidence in him, Tony goes to the mountain retreat as planned, unaware that Dorothy has arranged for them to spend the first evening alone. As Tony lies with his head in her lap in front of a cozy fire, Dorothy falls deeper in love with him, but is dismayed when, after confessing his love for her, he admits that Sylvia "wouldn't have him anyway." In spite of John's continued protests, Dorothy refuses to accept Tony's love until she has proven to herself that she, as a secretary, is his first choice. To that end, she pushes Tony to propose to Sylvia the next night, and as instructed by Dorothy, Sylvia accepts. Later, however, Tony sees Phillip sneak into Sylvia's bedroom, and the next morning, he slugs Phillip at the breakfast table and denounces Sylvia. As a last test of love, Dorothy explains to Tony that she had switched rooms with Sylvia. When Tony then carries her off in a display of masculine authority and marries her, Dorothy finally believes in his love. Although Dorothy insists on continuing her impersonation during her ocean cruise honeymoon, John surreptitiously orders the newly married couple to be given luxurious accomodations, delighting Tony with the ship's remarkable second-class service.