Gautier's novel tells the story of d’Albert—a young, handsome, and artistic gentleman of France who has a fascination with women and the feminine ideal.

His long search for a mistress comes to an end when his friend—who has an intimate knowledge of the appearances and characters of the women in their town—offers to take him on "a tour" of the local ladies, from which d’Albert selects Rosette as his target. He succeeds in winning her love, but after five months, their fantastic relationship falters as d’Albert grows bored.

Rosette—realizing that she must shake things up in order to keep her lover interested in her—arranges a series of feasts and parties at her country estate, to which she invites her old friend known as Théodor. d’Albert is entranced by the stranger's good looks and his skill as a huntsman, with a sword, and on a horse. He soon realizes he is in love with Théodor, and convinces himself that Théodor is, in fact, a woman in disguise, since he can't countenance being in love with a man.

One day, on hearing that d’Albert's favorite play is Shakespeare's As You Like It, the company insists on giving a performance with Théodor playing the heroine (as Rosette refused to put on man's clothes, as the role demands). Once he sees Théodor in women's clothing, d’Albert becomes convinced that he was correct in his belief that Théodor is actually a woman, and this conviction grows stronger as the play—with its various parallels to the company's situation—proceeds.

Thus, the "man" that both d’Albert and Rosette love is actually a woman by the name of Madelaine de Maupin, who has decided to dress as a man so that men will be honest with her about who they are without hiding behind flirtatious glamours.

After the play, d’Albert writes Madelaine de Maupin a letter, where he expresses his belief that she is a woman and his hope that she will reciprocate the deep affection he feels for her. She gives no reply, leaving d’Albert terrified that he was wrong and believing that he sent a passionate letter to a man. However, she meets with him one night (dressed in her costume from the play) to inform him that, since he is the only man to have ever seen through her disguise, he must be the man for her.

They share a perfect night, but it ends with tragedy when d’Albert wakes to find himself abandoned. Madelaine leaves a letter for him and Rosette to find, where she informs them that they have seen the last of her, though she also writes a private letter to d’Albert, informing him that, since they have had one perfect night, they should leave it at that and not ruin the dream. She also begs him to console Rosette and tells him that the two of them should live a long and happy together.