Act I, Part One
Algernon Moncrieff has his butler, Lane, prepare sandwiches for his aunt Lady Bracknell who is expected for tea along with her daughter, Gwendolen Fairfax, when Ernest Worthing (who goes by Jack) arrives. After Jack expresses his plan to propose to Gwendolen, Algernon forces Jack to explain what the inscription in a cigarette case means and Jack explains why he goes by two different names. While “Ernest” is the invented younger brother of Jack, Algernon reveals that he has also invented a friend named Bunbury, who affords him the chance to get away to the country whenever he wants.
Act I, Part Two
When Lady Bracknell and Gwendolen arrive, Algernon takes Lady Bracknell to the music room to give Jack and Gwendolen time alone. Gwendolen expresses her excitement and says that she could not think of marrying anyone whose name is not Ernest. When Lady Bracknell returns, she begins to question Jack about his background, which she finds scandalous. Jack tells Algernon his plans to get rid of Ernest, and claims that Cecily, his ward, and Gwendolen will soon become friends. When Gwendolen reenters, she asks Jack for his address in the country, which Algernon sneakily jots down.
Act II, Part One
Algernon, disguised as Mr. Ernest Worthing, arrives at The Manor House, Jack’s country estate in Hertfordshire, and meets Cecily, with whom he flirts as they head into the house to find food. When Jack arrives, he greets Miss Prism and Dr. Chasuble, and tells them that Ernest has passed away. He asks Dr. Chasuble about the possibility of being christened with the name Ernest himself.
Act II, Part Two
When Jack discovers Algernon, disguised as his own invented, and now presumably dead brother, he is apoplectic, knowing that he cannot expose Algernon without revealing his own deceptions, so he decides to go along with Algernon’s charade. When Gwendolen arrives, she is introduced to Cecily, who has come to believe that she is engaged to Ernest, so when Cecily tells Gwendolen that she is to marry Ernest, Gwendolen points out that this is impossible as she herself is engaged to Ernest Worthing. When Jack and Algernon arrive, the two women demand to know where Jack’s brother Ernest is, and Jack is forced to admit that he has no brother, leading the women to depart arm in arm.
Act III, Part One
Algernon and Jack explain the motives behind their duplicity and are subsequently forgiven by Cecily and Gwendolen when they reveal that they both have had arrangements to be rechristened “Ernest.” As the couples embrace, Lady Bracknell arrives and asks about Algernon’s friend Bunbury, which forces Algernon to declare that he is dead. Lady Bracknell learns of Algernon and Cecily’s engagement, excited to hear that Cecily is worth a great deal of money. However, she refuses to allow Jack to marry Gwendolen, and she summons Miss Prism.
Act III, Part Two
Lady Bracknell questions Miss Prism about the whereabouts of a certain baby that Miss Prism had lost years ago, and upon hearing that she had also left a handbag, Jack exits the room, returns the handbag to her, and throws his arms around Miss Prism, believing to have discovered his true parentage. Lady Bracknell reveals, however, that Jack is in fact the son of her poor sister, making him Algernon’s older brother, yet his true name is unknown, though Lady Bracknell suggests he was named after his father. When Jack searches recent military records, he discovers that his father’s name turns out to have been “Ernest John,” meaning that Jack has been telling the truth about his name being Ernest, as well as having an unprincipled younger brother. Gwendolen forgives Jack, and in the end, Jack acknowledges that he has discovered “the vital Importance of Being Earnest.”