La Fausse Suivante plot
A beautiful aristocratic young woman disguises herself as a knight in order to discover the true nature of her future husband Lélio. Lélio falls for her disguise and reveals to her that he is in love with a woman but that he must marry another woman, a countess, on pain of a large sum of money as compensation if he does not do so. However, he prefers the other woman because she is richer. If the Countess fell in love with another man now, his problems would be solved. The knight in disguise agrees to seduce the Countess, not to release Lélio from his marriage promise, but to reveal his true character.