Magnolia Hawks, whose father Cap'n Andy Hawks runs the show boat "Cotton Blossom," meets ne'er-do-well riverboat gambler, Gaylord Ravenal on the Natchez levee. The couple fall in love at first sight, then become actors on the showboat, marry, and move to Chicago. When Ravenal loses his money gambling, they separate and Magnolia has a tearful meeting with her father while singing at the Trocadero on New Year's Eve. She goes on to become a musical comedy star as does her daughter Kim, and years later she and Ravenal are reunited aboard the Cotton Blossom. A secondary plot involves Magnolia's mulatto friend, the tragic Julie LaVerne, and her devotion to her man, Steve Baker.