Lady Sneerwell, who in her youth was the target of slander, has set her life upon a course to reduce the reputations of other women to the level of her own. Aided by her intimate, Snake, she intrigues to involve the Teazles in scandal, to bring Joseph Surface’s true character to light, to wreck the love between Charles and Maria, and to gain Charles for herself along with Sir Oliver’s fortune. To her the world consists of nothing but scandal and scandalous intrigues, and she does her best to make her vision a reality. She is not successful, however, when she abuses Charles Surface to Sir Peter Teazle’s ward Maria, who refuses to listen to her. Instead, Maria trustingly confides in Lady Candour, whose defense of a reputation ensures its complete annihilation.
Sometimes Sir Peter Teazle ponders the wisdom of his marriage to Lady Teazle, doubting the judgment of an old bachelor in marrying a young wife. Lady Teazle is a country-bred girl who is enjoying London life extravagantly and to the full. Sir Oliver Surface is concerned about his two nephews, his problem being the disposal of his great fortune. Sir Oliver has been abroad for the past fifteen years and feels that he does not know his nephews’ real natures; he hopes by some stratagem to catch them unawares and thus be able to test their characters.
One day, Sir Peter and Lady Teazle quarrel because Sir Peter violently objects to her attendance at the home of Lady Sneerwell. Lady Teazle accuses Sir Peter of wishing to deprive her of all freedom and reminds him that he has promised to go to Lady Sneerwell’s with her. He retorts that he will do so for only one reason, to look after his own character. When they arrive, Lady Sneerwell’s rooms are full of people uttering libelous remarks about their enemies and saying even worse things about their friends. Sir Peter escapes as soon as possible.
When the rest of Lady Sneerwell’s guests retire to the card room, leaving Maria and Joseph alone, Joseph once more presses his suit. He insinuates that Maria is in love with Charles and is thus running counter to Sir Peter’s wishes. Lady Teazle walks in just as Joseph is on his knees avowing his honest love. Surprised, Lady Teazle tells Maria that she is wanted in the next room. After Maria leaves, Lady Teazle asks Joseph for an explanation of what she has seen, and he tells her that he was pleading with Maria not to tell Sir Peter of his tender concern for Lady Teazle.
Sir Oliver consults Rowley, Sir Peter’s shrewd and observing servant, in an attempt to learn more about his nephews’ characters. Rowley himself believes that Joseph does not have as good a character as his reputation seems to indicate and that Charles has a better one. Sir Oliver also consults Sir Peter, who declares that he is ready to stake his life on Joseph’s honor. He is much put out, therefore, when Maria once more refuses to marry Joseph.
Sir Peter, Sir Oliver, and Rowley plan to test the worthiness of the nephews. Charles is, as usual, in dire need of money, and Sir Oliver arranges to accompany a moneylender who is going to see Charles; Sir Oliver will claim to be Mr. Premium, a man who can supply the money that Charles needs. When they arrive at Charles’s lodging, a drinking party is in progress, and some of the guests are playing games of dice. Sir Oliver is not at all impressed with Trip, Charles’s footman, who gives himself the airs of a fashionable man-about-town.
Upon investigating, Sir Oliver discovers that Charles has, with the exception only of the portraits of his ancestors, turned all of his inherited possessions into cash. Convinced that Charles is a scamp, Sir Oliver, still calling himself Premium, agrees to buy the paintings, and he purchases each picture as presented except his own portrait, which Charles will not sell for any amount of money. Sir Oliver is pleased by this fact and on that ground discounts Charles’s reputation for extravagance. Charles receives a draft for eight hundred pounds for the portraits and immediately sends one hundred pounds to Mr. Stanley, a poor relation whose financial circumstances are even worse than his own.
During an assignation between Joseph Surface and Lady Teazle in Joseph’s library, Joseph advises her to give her husband grounds for jealousy rather than to suffer his jealousy without cause. He argues that to save her reputation she must ruin it and that he is the man best able to help her. Lady Teazle considers such a doctrine very odd.
While they are talking, Sir Peter arrives unexpectedly, and Lady Teazle hides behind the screen that Joseph orders placed against the window. Joseph then pretends to be reading when Sir Peter walks in. Sir Peter has called to inform Joseph of his suspicions that Lady Teazle is having an affair with Charles; Sir Peter also shows Joseph two deeds he has brought with him, one settling eight hundred pounds a year on Lady Teazle for her independent use, the other giving her the bulk of his fortune at his death. Joseph’s dissimulation before Sir Peter and Sir Peter’s generosity to her are not lost on Lady Teazle. When Sir Peter begins to discuss Joseph’s desire to wed Maria, Lady Teazle realizes that Joseph has been deceiving her.
Below stairs, Charles inopportunely demands entrance to the house to see his brother. Not wishing to see Charles, Sir Peter asks Joseph where he can hide. Sir Peter catches a glimpse of a petticoat behind the screen, but Joseph assures him that the woman behind the screen is only a French milliner who plagues him. Sir Peter hides in a closet, and Lady Teazle remains in her hiding place behind the screen.
When Charles comes in, he and Joseph discuss Lady Teazle and Sir Peter’s suspicion that Charles is her lover. Charles mentions that he believes Joseph to be her favorite and recounts all the little incidents that lead him to think so. Embarrassed by this turn in the conversation, Joseph interrupts to say that Sir Peter is within hearing. Placed in a difficult position, Charles explains to Sir Peter that he has merely been playing a joke on Joseph. Sir Peter knows a good joke on Joseph, too, he says: Joseph is having an affair with a milliner. Charles decides that he wants to have a look at the milliner and pulls down the screen, revealing Lady Teazle. Joseph is undone because Lady Teazle refuses to agree with any of the excuses he makes. She angrily informs her husband of the whole nature of Joseph’s intentions and departs. Sir Peter follows her, leaving Joseph to his own conscience.
Sir Oliver, masquerading as Mr. Stanley and badly in need of assistance, gains admittance to Joseph’s apartment. Joseph refuses to help Mr. Stanley, saying that he receives very little money from Sir Oliver and claiming that he has advanced all his funds to Charles. After Sir Oliver leaves, Rowley, who is a party to the whole scheme, comes to tell Joseph that Sir Oliver has arrived in town.
Sir Oliver goes again to see Joseph. Still believing that his uncle is Mr. Stanley, Joseph is showing him out just as Charles enters. Charles, surprised to see the man he knows as Mr. Premium in his brother’s apartment, also insists that he leave, but at that moment Sir Peter Teazle arrives and addresses Sir Oliver by his right name. Both Sir Oliver and Sir Peter are now aware of Joseph’s real character. Charles, promising to try to reform, gets Maria and his uncle’s inheritance as well. Lady Sneerwell is exposed by Snake, who is paid double to speak the truth, and Lady Teazle returns her diploma to the School for Scandal, of which Lady Sneerwell is president. Everyone is happy except Lady Sneerwell and Joseph Surface.