Arnolphe, the protagonist, is a mature man who has groomed the young Agnès since she was 4 years old. Arnolphe supports Agnès living in a nunnery until the age of 17, when he moves her to one of his abodes, which he keeps under the name of Monsieur de la Souche. Arnolphe's intention is to bring up Agnès in such a manner that she will be too ignorant to be unfaithful to him and he becomes obsessed with avoiding this fate. To this end, he forbids the nuns who are instructing her from teaching her anything that might lead her astray. Right from the very first scene, a friend of his, Chrysalde, warns Arnolphe that such a scheme will likely fail, but Arnolphe takes no heed.
After Agnès moves into Arnolphe's house, Arnolphe meets by chance Horace, the young son of Arnolphe's friend Oronte, whom Arnolphe had not seen in years. Not realizing that Arnolphe and Monsieur de la Souche are the same person, Horace unwittingly confides to Arnolphe he had been visiting Agnès for the past week while the master of the house, one Monsieur de la Souche, was away.
Arnolphe then schemes to outmaneuver Horace and to ensure that Agnès will marry him.
Arnolphe becomes more and more frustrated as the play goes on. Agnès continues to meet with Horace despite Arnolphe's displeasure until, finally, a misunderstanding leads Arnolphe to believe that Agnès has agreed to marry him and Agnès to believe that Arnolphe has given her permission to marry Horace. When they realize the actual situation, Arnolphe forbids Agnès from seeing Horace. Horace, in his distress, comes to Arnolphe, asking for his help in rescuing Agnès from "Monsieur de la Souche".
In the final act Oronte and Enrique arrive and announce that Horace is to marry Enrique's daughter. The daughter turns out to be Agnès, rendering all of Arnolphe's scheming useless.
