The play opens in the "morning-room" of the Windermere house, where Lady Margaret Windermere is arranging roses in preparation for a "small but select" ball she and her husband are hosting that evening in honor of her birthday. Parker, the butler, announces that Lord Darlington has come to call, and shows him in. Darlington begins to flirt with Lady Windermere, who very kindly but firmly tries to discourage his attentions. She says she does not like compliments but tells him she thinks he is really a good man who is only pretending to be worse than most men. He answers that, "so many conceited people go about Society pretending to be good, that I think it shows rather a sweet and modest disposition to pretend to be bad."
Lady Windermere makes it plain that she is not going to stoop to the Victorian fad of exaggerated flirtation, and despite the clues Darlington gives her, she remains unaware that he is actually in love with her. He finally makes a thinly disguised accusation that her husband is having an affair with another woman, but she doesn't pick up on that either. Finally, the Duchess of Berwick and her daughter, Lady Agatha Carlisle, are announced and ushered into the morning room. In the course of the Duchess' silly chatter, the accusation against Lady Windermere's husband is made so plainly that Lady Windermere can't misunderstand. The Duchess tells Lady Windermere that her husband has been seen often with a Mrs. Erlynne. She also tells her that Lord Windermere is suspected of having paid Mrs. Erlynne enormous sums of money.
Lady Windermere at first refuses to believe it, protesting to the Duchess, "It's impossible! We are only two years married. Our child is but six months old!" But as soon as her guests leave, Lady Windermere struggles between wanting to trust her husband, and wanting to examine his bankbook to discover whether he has really been having an affair. She finally goes to his desk and pulls out his bankbook to examine it. To her relief, she finds nothing. However, as she's returning it to its place, she notices another book, this one locked. She cuts it open and finds Mrs. Erlynne's name on page after page, accounting the different sums that have been paid to her over a period of time. Just as the truth of her husband's infidelity becomes apparent to Lady Windermere, her husband walks into the room and asks whether she has received the birthday present he has sent her - a fan, inscribed with her name. He sees his private bankbook in her hands, and she confronts him with the evidence of his affair. Lord Windermere admits that the woman has made some mistakes in the past, but insists she is trying to improve herself and that he is not having an affair with her. He claims he has never loved anyone but his wife, but does not explain why he is paying Mrs. Erlynne. His wife, therefore, cannot believe the relationship is innocent, and is insulted when he then asks her to help Mrs. Erlynne back into society's good graces by inviting the woman to her birthday ball that evening. When Lady Windermere refuses to do it, he writes the invitation himself, and his wife promises that if he invites Mrs. Erlynne, she will publicly insult the woman. She leaves the room, and the mystery about Mrs. Erlynne is heightened when Lord Windermere says, "What shall I do! I dare not tell her who this woman really is. The shame would kill her."
Act Summary 2
The second Act takes place in the drawing room of the Windermere house, with the activity of the ball visible through an adjoining doorway. Lady Windermere is receiving her arriving guests, and the Duchess of Berwick is sitting nearby managing her daughter's dance card.
As the guests arrive, Lord Windermere tries to speak to his wife again, but she is busy greeting people, and he falls into a conversation with Lord Augustus Lorton. Lord Augustus begins asking Windermere about Mrs. Erlynne, and it becomes evident to the audience that Lord Augustus is...