Sixteen-year-old actress Ann Winters, who has been a movie star since childhood, declares that she no longer wants to play "childish" roles. Her attitude irritates her agent, Harry Fabian, who tells her that the studio has decided that her next picture will be Ann of Honeysuckle Farm , in which she is to play a twelve-year-old. Ann leaves a note for her sympathetic secretary, "Biggy" Biggsworth, saying that she does not want a career if she cannot have a life, too, then runs away for a two-week vacation. Just then, innocent Penny Ryan from Oriole, NE arrives. Penny is the winner of a contest concocted by Harry in which the fan who most resembles Ann gets to spend two weeks with her in her home. Harry and Biggy are stunned by Penny's appearance, for she is an exact double for Ann. Harry decides to induce Penny to impersonate Ann, who is to start her new film the next day or else be suspended by the studio. Penny's first test comes shortly after her arrival, with the visit of "The 20 Minus Club," a group of former child stars who have not enjoyed Ann's continued success. Included in the group is Johnny Kelly, Ann's former co-star and boyfriend. The kids plead with Penny, whom they believe is Ann, to join their "Junior Victory Caravan" show, with which they want to entertain the troops. Harry signals to Penny that Ann could not get involved with such a project and Penny reluctantly declines. While Penny is settling into her life as Ann, the real Ann runs out of gas on a mountain road and goes to a nearby house, which is the residence of playwright Oliver Lawrence. Ann tries to hide her identity so that Oliver will not regard her as a child, and he agrees to let her spend her holiday at his home, with his housekeeper Mammy as chaperone. Ann develops a crush on the charming writer, while Penny spends more time with The 20 Minus Club. After viewing their show, Penny really believes in the kids, but must deflate their hopes by saying that she is above such amaturish endeavors. Disillusioned by Hollywood scheming, Penny decides to return home, but Biggy reveals Ann's whereabouts and suggests that Penny consult her about the show. Penny rounds up the gang, and Johnny drives them to Lawrence's home. Ann is shocked by Penny's appearance, but quickly asserts that she and Oliver are practically engaged, and that she has given up film work for the theater. Oliver overhears their conversation and realizes the seriousness of Ann's crush on him. He tells Penny not to give up hope, then sends for his daughter Jennifer. Oliver tells Ann that Jennifer is "the woman in his life," and Ann, believing that Jennifer is his girl friend, runs outside. There she meets Johnny, who thinks that her tearful mien is because she wants to do the show but cannot because of her own career pressures. Johnny tells her how "swell" he thinks she is, and Ann realizes how much he and the other kids mean to her. Soon after, Ann, Johnny and the kids stage their show, and Penny is a member of the appreciative audience.