Jules, the Prince of Bramante, has been disappointed in his hopes of having a male heir. His oldest son and wife produced only a girl child, then died. Jules decides to have their child, Gabriel, raised as a boy. She is to be instructed that women are mindless slaves to men, born to suffer, so that when, at adolescence, her sex is revealed to her, she will decide to accept instead the sex her grandfather has given her.

When she is told the truth, Gabriel does not abandon her male costume or demeanor, but she does want to make sure that Astolphe, her cousin who should rightfully inherit the family fortune, has all the money he needs. She sets out to find him. They meet in a bar and before Astolphe learns her identity, they fight with some thieves and are taken to prison. In prison, they swear life-long affection and decide to travel together, winding up in Venice for the carnival.

Astolphe, who has long been disturbed by his attraction to the gentle Gabriel, asks her to dress as a woman to attend a masquerade. She agrees, and he is dumb struck by her appearance. Every man at the ball falls in love with her and when Astolphe reveals that (as he believes) she is really a man, many are astonished. When Astolphe returns home that night, he catches a glimpse of Gabriel undressing and realizes that she is a woman. They become lovers.

Gabriel dresses as a woman and becomes submissive. But Astolphe is unable to achieve the higher love to which Gabriel aspires. He is consumed by jealously, finally locking Gabriel in her room. She escapes and leaves him, returning to her male identity. The story ends when Gabriel is murdered by a man hired by her grandfather to cover up her disobedience. Sand revised the play in 1850 and made Gabriel into a much less independent character named Julia.