Bellezza (Beauty) admires herself in the mirror, but knows that her beauty will one day pass. Piacere (Pleasure) tries to cheer her up, promising her eternal beauty if she remains only faithful to pleasure. Bellezza promises never to leave her, or else to accept severe punishment.
Piacere warns of the destructive power of useless worry, but now Tempo (Time) and Disinganno (Disillusion) get involved in the conversation. Together they seek to explain the ephemeral nature of beauty, which quickly wilts like a blossom. Piacere challenges them to a competition: Bellezza is now convinced that time can do nothing to her beauty.
Arguments are quickly exchanged. Tempo points out that one needed just to open the graves to be convinced of the decay of beauty; Bellezza and Piacere consider it a vain waste of time to be concerned with thoughts of death already in youth. Disinganno compares the limited nature of earthly life with the endlessness of time. Piacere calls time a disagreeable factor that should be ignored in order to enjoy life.
Tempo and Disinganno now argue that self-destruction is part of human nature, while time constantly renews itself. Piacere presents Bellezza, who has now become pensive, with all conceivable pleasures. She receives unexpected support when a graceful youth with seductive sounds recalls the eternal beauty of music. Bellezza is convinced that time can never rob her of this pleasure, but again the two adversaries are able to cast doubt: if Bellezza will not accept the passing of time on earth, she should at least be concerned about her survival in eternity before it is too late.
Unsure, Bellezza agrees for once to cast eyes on the truth, which Tempo and Disinganno claim to represent, to see for herself that this is where true pleasure is to be found. Piacere warns against this, to no avail.
Tempo beckons Bellezza to look into the mirror of truth, while Piacere pleads that she shields her eyes from it. Tempo explains that her life is divided into three parts: the past, which she has wasted uselessly, the present, which is passing by at that very moment, and the future, which remains concealed to her if she refuses to face the truth.
Bellezza can find nothing pleasurable about these explanations, but is worried about her future, which suddenly seems threatening. Now furious, Piacere reminds her of her vow to accept a dire fate if she renounces pleasure.
Bellezza cannot decide, and hopes for a compromise. She would to bear two hearts in her bosom: one for pleasure, the other for remorse. Tempo and Disinganno take advantage of her uncertainty and vividly portray the advantages of a virtuous life. For Beauty too, they argue, it is still not too late to change her ways and to repent her mistakes.
Bellezza asks for time to decide. But time—as Tempo reminds her—is with her. Despairingly, Bellezza seeks a way out, but Disinganno’s responses rob her of all illusion.
Once more she asks Piacere not to make life unnecessarily difficult, for time will catch up with her in the end, but the sad tone in which this request is made brings about a decision: Bellezza wants to change her life, and in the hour of death to appear before God without remorse. She surrenders to the guidance of Tempo and Disinganno. Her beauty now seems reprehensible to her; she puts aside her jewelry, requesting instead to be draped in sackcloth, and curses the fact that she ever came to know pleasure. Furious, Piacere rushes off.
Bellezza has decided to spend the rest of her days as a nun in a remote cloister. She pleads to the heavens for succor.