In 1904, Uncle Latsie [S.Z. Sakall] Dolly brings his two nieces to New York from Hungary, and the girls—Jenny [Betty Grable] Dolly and Rosie [June Haver] Dolly—immediately take to cafe dancing, dazzling locals with their charm and rhythm. By 1912, still performing, they pivot to vaudeville to help settle Uncle’s mounting card debts, chasing bigger stages and brighter lights. In their path to the limelight, they cross paths with another rising act, the singer Harry Fox [John Payne], and Jenny [Betty Grable] (Dolly) falls hard for him.
Harry [John Payne] struggles to emerge while Jenny and Rosie’s starpower climbs, and Rosie [June Haver] watches with a wary eye as Jenny’s feelings deepen for the man they both hope will lift them higher. Harry pours a newly composed tune into Jenny’s ear, his voice carrying a promise of fame, and soon a willing producer recognizes the promise in his music, offering the break he’s been waiting for. The partnership ripens into a marriage, and Jenny [Betty Grable] Dolly and Harry Fox [John Payne] glide toward domestic bliss as their careers begin to fuse with shared success.
But the looming shadow of war interrupts their ascent. Europe’s conflict pulls Harry away, and while he serves, Rosie [June Haver] urges Jenny to take an engagement with the Folies Bergère in Paris, a decision that expands their reach across continental stages. They tour Europe, winning admirers and building reputations, even as the war winds down. When Harry returns home and asks Jenny to come back, Rosie urges otherwise, insisting the show must continue. The tension between loyalty and ambition grows, and Harry’s comments hint at a possible divorce.
The Dolly Sisters press onward through Europe, and Jenny [Betty Grable] dives into gambling and pursues relationships with wealthy suitors, while Rosie [June Haver] remains intensely focused on keeping the act together. Rosie’s secret engagement with her American boyfriend Irving Netcher [Frank Latimore]—a man who owns department stores—adds another layer of complexity to their intertwined lives. Rosie’s plan to leave the act unsettles Jenny, who overhears the plans and, in a moment of impulse, decides to accept a marriage proposal of her own, choosing between a future with Harry and the life she might have with someone new.
A reckless night drives Jenny to a heartbreaking moment; as they drive away from a party, memories of Harry overwhelm her, and she crashes the car. Meanwhile, Harry [John Payne] announces that he is engaged to Leonora Baldwin [Trudy Marshall], a development that stirs concern and reflection among the siblings as the distance between dream and duty grows. After months of healing in a French hospital, Jenny returns to New York, her resolve tempered by time and memory.
Back in the spotlight, a benefit show becomes a reunion for the Dolly Sisters; Jenny [Betty Grable] Dolly and Rosie [June Haver] Dolly take the stage once more as a duo, embodying the long-shared history that shaped their act. Harry Fox [John Payne] also returns to the stage, and he introduces Lenora Baldwin [Trudy Marshall], a moment that crystallizes the ache of what might have been, as Lenora realizes that Harry still loves Jenny. Tension crackles in the theater, but the night culminates with Jenny and Rosie joining Harry on stage to finish his number, a final act that seals their enduring bond as the Dolly Sisters and marks the end of one chapter while suggesting the enduring grip of another.
