In 1904, Uncle Latsie (S.Z. Sakall) comes to New York from Hungary with two little nieces, Jenny (Betty Grable) and Rosie (June Haver) who immediately take to cafe dancing. In 1912, they're still at it, but to pay Uncle's card debts they decide to go into vaudeville. They meet another up-and-coming act, singer Harry Fox (John Payne). Jenny falls in love with him.
Harry struggles while the sisters' fame rises. Rosie is distrustful but Jenny dates him anyway. Harry sings to Jenny the latest song he has composed. A producer hears it and gives him the break he's been waiting for. Jenny and Harry get married but, just as success comes to Harry, war in Europe breaks out and he enlists.
Rosie persuades Jenny to take an engagement with the Folies Bergere in Paris. As they tour Europe and achieve more success and admirers, the war ends. Harry asks her to come home but Rosie asks her to stay with the show. Harry insinuates there should be a divorce. The Dolly sisters continue their tour of Europe, where Jenny takes to gambling and dates one of her wealthy suitors.
Rosie is secretly engaged to her American boyfriend Irving Netcher (Frank Latimore), who owns department stores. Now she plans to leave the act but Jenny overhears this and decides to accept a marriage proposal. As they drive away from a party, Jenny is overwhelmed by memories of Harry and ends up crashing the car. Harry, who just got engaged to Leonora Baldwin (Trudy Marshall), shows his concern. After several months of recovering in a French hospital, Jenny returns to New York. During a benefit show, she and Rosie reunite as Dolly Sisters. Harry, who also performs, introduces Leonora, who realizes that Harry still loves Jenny and leaves the theater during Harry's act. On stage, Jenny and Rosie both join Harry to finish his number.
Directed by Irving Cummings
Produced by George Jessel
Written by John Francis Larkin
Marian Spitzer
Starring Betty Grable
June Haver
John Payne
Music by Alfred Newman
Cyril J. Mockridge
Charles E. Henderson
David Buttolph
Cinematography Ernest Palmer
Edited by Barbara McLean