Madame Pernelle is visiting her son Orgon's house and uses the opportunity to criticize all the members of the household and to praise a visitor named Tartuffe because he is a man of holiness and zeal. The other members of the family object, believing that Tartuffe is hypocritical. Madame Pernelle will not accept such ideas. She admonishes everyone to follow Tartuffe's precepts. After Madame Pernelle leaves, Cleante, Orgon's brother-in-law, and Dorine, a maid, discuss the situation, and they agree that Tartuffe has deceived Madame Pernelle and Orgon. Orgon's son, Damis, wonders if his father will still allow his daughter Mariane to marry her true love, Valere. Damis is concerned because he wants to marry Valere's sister, so he asks Cleante to question Orgon about his promise to allow the marriage to take place. When Orgon arrives, he seems much more concerned about the welfare of Tartuffe than anything else, including his wife, who has been ill. Cleante tries to discuss with Orgon the influenceTartuffe has had upon the household, but Orgon is only interested in singing Tartuffe's praises. When Cleante questions Orgon about what can be done about Tartuffe, he refuses to give an answer. However, when his daughter Mariane arrives, Orgon tells her he wants to bring Tartuffe into his family by the marriage of Mariane to Tartuffe. Mariane is shocked at the news. Dorine, the maid, later reprimands Mariane for not having refused with determination to the marriage proposal. Mariane's is in love with Valere, who accuses her of consenting to the marriage with Tartuffe. Dorine listens to them argue, and then promises to help them prove that Tartuffe is a hypocrite. Damis, Orgon's son, is also determined to reveal Tartuffe's hypocrisy. When Elmire and Tartuffe have occasion to meet alone, Damis hides in a closet and listens. Tartuffe, thinking he is alone with Elmire, suggests they become lovers. Damis bursts from the closet and threatens to expose Tartuffe's plans. When Orgon arrives, Damis tries to convince him regarding Tartuffe's proposition, but Orgon refuses to believe it. He believes his son is evil for trying to defame Tartuffe. He then disinherits his son. Orgon states his intention to make Tartuffe his sole heir, as well as his son-in-law. Cleante later confronts Tartuffe and tries to reason with him, but Tartuffe will only respond in religious cliches. Orgon and Elmire arrive, and when she hears Orgon's plans, she extracts a promise from him to hide and observe Tartuffe's actions. Orgon consents, and Elmire sends for Tartuffe. When he arrives, he is accosted by Elmire, and soon he begins to make declarations of love to her. Finally convinced of Tartuffe's hypocrisy, Orgon orders him from the house. Tartuffe then reveals that he is now the legal owner of the house, since Orgon has signed over his property. Orgon reveals that he is frightened because he has previously entrusted some secret documents to Tartuffe's care--documents which could ruin Orgon's relationship to the Prince. Despite the numerous calamities that have befallen Orgon due to his own gullibility, surprising events transpire, and all ends well at last."