After her client Albert Osborne (Robert Benchley) makes a pass at her, Susan Applegate (Ginger Rogers) quits her job as a scalp massager for the Revigorous System and decides to leave New York City and return home to Stevenson, Iowa. Upon arriving at the train station, she discovers she has only enough money to cover a child's fare, so she disguises herself as a twelve-year-old girl named Su-Su. When a suspicious conductor catches her smoking, Su-Su takes refuge in the compartment of Major Philip Kirby (Ray Milland) who, believing she is a frightened child, agrees to let her stay with him until they reach his stop.