The Smith family leads a comfortable, happy existence in St. Louis, where the 1904 World’s Fair is set to happen. Seventeen-year-old Esther (Judy Garland) has fallen in love with the boy next door, though he hardly notices her. When Mr. Smith announces that he has been transferred to New York for business, the family is unhappy at the thought of leaving St. Louis, their lives, and the World’s Fair behind.