Hotel barber Joe Jenkins (Jack Haley), who's obsessed with newspaper stories about high-society celebrities, is dragooned into posing as eccentric millionaire Aloysius Merriweather (Monroe Owsley) at a fancy weekend party. At first thrilled at the prospect of hobnobbing with the 400, Joe is less than thrilled when he's forced to continue the charade after Merriweather is rendered unconscious in a traffic accident. Getting off to a bad start with heiress Patricia Randolph (Betty Furness) -- who loses her speedboat, beach house and clothes thanks to his bumbling -- Joe redeems himself by saving her father's (Raymond Walburn) automobile business. Whether or not he can save himself from Spike Nolan (Tom Dugan), the gun-wielding brother of Owsley's neurotic bride Mazie (Rosina Lawrence), is another matter! Mister Cinderella is a typically frantic farce from the Hal Roach comedy mills, with a marvelous scene-stealing performance by Arthur Treacher and a brisk musical score (culled mostly from Roach's Laurel & Hardy and "Our Gang" comedies) by Marvin Hatley and LeRoy Shield.