Valcour has been hopelessly in love with Léontine, a beautiful young widow, for years. With the help of his friend Ophémon, Valcour has been showering Léontine with gifts, flowers, and love letters. He has done so anonymously; Léontine felt betrayed after her late husband’s death and Valcour is certain that she has no interest in romance. He tells Ophémon that he has lost all hope of winning her affections, while Ophémon responds that it is time for Valcour to reveal his secret. Léontine accidentally overhears this conversation and learns that she is madly loved by Valcour. 

Léontine, trying to conceal her new knowledge that Valcour loves her, asks him to settle a dispute she is having with her friend Dorothée. The anonymous lover has sent Léontine a bouquet of flowers along with a letter asking her to carry it at a wedding later that day; if she doesn’t, he will take it as a sign that he should leave her alone. Dorothée thinks that it would do no harm for Léontine to accept the flowers. Wanting to see Valcour’s reaction, Léontine claims she does not want to hurt her secret admirer, but doesn’t want to lead him on either. Valcour convinces Léontine to carry the bouquet. 

Jeannette and Colin, a young couple about to be married, express their thanks to Léontine for making their wedding possible. They hope that everyone might be as filled with love and joy as they are. Léontine is surprised, but this wedding seems to be one of the festivities the anonymous lover regularly organizes for her. The guests are enthusiastic to prepare the wedding and the joy is contagious.

Dorothée, Léontine, and Valcour find themselves alone for a brief moment as all guests start the festivities. Valcour tells Léontine that the anonymous lover might very well be watching them nearby, and convinces her to call out to and ask him to reveal himself. When she does so, Valcour overdramatically answers that he himself is the tormented anonymous lover.  Léontine feels overwhelmed, even dizzy.  Valcour and Ophémon quickly try to convince Léontine that it was all in jest, while Jeannette and Colin are sympathetic to Léontine’s obvious emotional distress.  

Later that evening, Léontine laments that Valcour is unlikely to understand her feelings, and wishes she could unburden her heart to him. Ophémon, pushed by Valcour, arrives and improvises news that he has spoken to the anonymous lover. Pressed by Léontine, Ophémon says the anonymous lover worries that it would be impossible for Léontine to love him, but wishes to reveal his identity anyway. Léontine agrees to the meeting. 

As she awaits the arrival of her not-so-secret admirer, Léontine reflects that her heart is now full of unexpected passion. When Valcour shows up, explaining that he’s just there to be her supportive friend, Léontine desperately tries to get him to confess his love for her. As Ophémon, Dorothée, and eventually the whole village listen outside the door, Léontine and Valcour finally confess their love for each other. Valcour is about to reveal that he himself is the Anonymous Lover when Léontine kisses him, putting an end to the conversation. 

Léontine and Valcour join Jeannette and Colin for what is now a double wedding. The two couples celebrate their happiness with songs and dances.