Dr. Molnac and his musical troupe; Beggs, the manager; Mitzi Martos, a singer; Mitzi's agent Pauline; society scion Barry Saunders and his "keeper" Oliver Goodwin, are en route to Santa Barbara. Barry falls for Mitzi while trying to loosen her slipper caught between two railroad cars, but she mysteriously leaves before he can learn her name. Barry and Oliver take a suite at the Casa Barbara, where they hire the house detective, Parkyakarkus to find the slipper's owner but he bungles the job. Oliver reminds Barry that he will lose his mother's $3,000,000 inheritance if he weds before the age of thirty. Mitzi and Pauline also register at the hotel, hoping to induce Dr. Molnac, performing there, to give Mitzi an audition. Also arriving are Mitzi's mother, Countess Martos and her wealthy friend Mrs. Penner and her son Joe, and the mothers have intentions of Joe marrying Mitzi. Barry finally meets Mitzi, and proposes marriage at a date three years in the future. To break up the romance, Joe and Parky steal Mitzi's shoe wardrobe and she, thinking Barry did it, rushes to his room in her negligee, upbraids him and stalks out. He, in his dressing gown, follows her to her room and they are about to reconcile when Mitzi's mother and Joe and his mother enter. Barry hides in another room and overhears Mitzi's mother blandly suggesting that Mitzi marry Joe. Mitzi, not pleased at this prospect, tells them she is already married and Barry, taking the cue, enters and plays the role of the new husband. Mitzi's mother promptly has them booked into the bridal suite. Pauline and Oliver arrange a wedding party with Dr. Molnac's troupe performing and Pauline, still scheming to get Mitzi an audition, hires Joe and Parky to kidnap Molnac's singer, Susan. Mitzi is a smash hit, and Barry's mother arrives and announces she had lied about his age and he is really thirty, and can get married without losing his inheritance.