London 1905. A distressed solitary gentlewoman rides by carriage in Hyde Park. She is observed from the sidewalk by two men - one comments on her sad demeanour. She re-gains composure before arriving at a grand house, where rumour is rife amongst the gossiping ladies. The new arrival is Lady Wellwater, who is to be matron of honour at the wedding of Bouncie Barrington, Bouncie having ditched her earlier admirers. Lady Wellwater's husband Digby arrives separately, but her thoughts are elsewhere. Hearing a street band play a wistful waltz 'Dreaming', she presses her face to the window, sees a little girl waltzing around the musicians, and thinks back to times past when she was on the stage.

Many years earlier. Teenage 'Trottie True' attends a performance at the Bedford Music Hall with her parents and sees 'the great little Jessie' sing. Trottie enters a talent night, at first against her mother's wishes. Billed as 'Little Trottie True' she is encouraged by fellow artiste Joe Jugg.

Several years later; Trottie is top of the bill. Joe tells her that he is going 'legit' by joining the cast of a George Edwardes musical comedy 'The Belle and the Buoy' at the Gaiety, and he invites her to join him.

At home, while gathering in the laundry, a balloon falls from the sky and crash-lands on the greenhouse. The pilot is Sid Skinner, a self-styled 'pioneer' balloonist. He invites Trottie out and they picnic on Box Hill.

Trottie appears in Bradford with the Gaiety show, performing with Joe Jugg and Daisy Delaware. Gaiety impressario George Edwardes suggests that Trottie has supper with show investor Arthur Briggs (after which Briggs makes amorous advances), even though it means she has to stand up Sid. Sid arrives at the theatre, talks with Joe, and both men declare their love for Trottie. She returns to theatre, and argues with Sid, but they make up the next morning as he leaves by train.

At the Gaiety Theatre London, Trottie shares a dressing room with star 'Bouncie' Barrington, who explains that she is there to be looked at, not listened to. Bouncie says she expects to marry Monty, Marquis of Maidenhead, who is waiting outside with other aristocratic 'stage door johnnies'. The show is a success and Bouncie assesses her 'trophies'. Monty introduces his pal Lord Digby to Trottie and Digby invites her to supper. He romances Trottie, but is worried about what his sceptical mother will think. Throwing caution to the wind, he asks Trottie to marry him.

Trottie becomes the new Lady Wellwater. At the annual servant's ball, Trottie opens dancing by waltzing with chief butler Saintsbury, and entertains the crowd with a music hall number. Digby's mother is displeased, but when Trottie sings 'White Wings', all present are visibly moved, and Trottie is accepted into the family. Trottie and Digby are happy and in love.

Later, Bouncie (now Lady Maidenhead and married to Monty) visits, and they compare lives as gentry wives. Bouncie complains Monty is unfaithful, and Digby is seen in society with another Gaiety Girl, Ruby Rubato.

Passing the Albert memorial, Trottie spots Sid, and they lunch at Romanos. At another table, Trottie sees Digby entertaing Ruby. Trottie and Digby argue over their extra-marital affairs. To make him jealous, Trottie agrees to a rendevous with Monty's pal, the 'most attractive bounder' Breckenham, but her virtue remains intact.

Trottie attends a balloon festival at Roehampton with Sid. She and Digby are the subject of gossip, due to his suspected infidelities. After a row with Digby, Trottie takes a balloon ride with Sid, but when he tells Trottie he is to marry Violet, an agitated Trottie causes the balloon to crash, and they are rescued.

1905. Trottie turns away from the window and her memories. Monty informs Digby that Bouncie has left him to marry Claude, a chauffeur. Digby suggests to Trottie that they return home together. As their carriage travels through the park, they embrace and make up. Both look happy. They are watched by the same two sidewalk observers again, as Joe Jugg smiles sardonically to Mr True.