Susan Applegate (Ginger Rogers) has been living in New York for the past year and has decided she wants to return to her hometown in Iowa. Unfortunately the train fare has gone up and not wanting to stay in NYC a day longer she decides to pose as a 12 year old to get a half priced ticket. She is befriended by a kindly solider Major Philip Kirby (Ray Milland) and when the train is stranded because of a mud slide, he decides to take the “little girl” with him to his fiancé home. All chaos breaks out, when her home turns out to be amidst an all boy West Point like school, who are all too eager to impress young Susan. Things get more complicated when Susan starts to develop feelings for Philip.