Act I: Opens with an interaction between Luke and Phoebe. We learn that Alicia and Robert are engaged. Everyone is getting together for Sir Michael’s 70th birthday. Robert is late because he has run into his old friend, George Talboys, who accompanies him to Sir Michael’s birthday party. Alicia introduces them to Lady Audley via a miniature she carries with her. George recognizes his “dead” wife, wanders off, and ends up confronting Lady Audley. They have a long exchange, in which George vows vengeance. Lady Audley throws him down a well, not suspecting that Luke Marks has seen everything.
Act II: Alicia complains to her father that George’s disappearance has postponed her marriage to Robert. Luke confronts Lady Audley with his knowledge and extorts money from her. She promises to bring him 100 pounds at the tavern she bought for he and Phoebe upon their marriage, four months prior. After he exits, Robert enters, having returned from London, where he was searching for George. He converses with Lady Audley, and then eventually confronts her with his suspicions that she is Helen Talboys, and that she has done some sort of mischief to George. They agree to be eternal foes, and then Robert offers to let her leave Audley Court in exchange for his silence; otherwise, he will publicize his suspicions. After he leaves, Lady Audley accuses him to Sir Michael and Alicia of hitting on her, and asks Sir Michael to banish him from Audley Court, which request Sir Michael promptly complies with. Robert heads to Mt. Stanning, where Luke is drunk and bragging about that fact that he has a secret about Lady Audley. Robert tries to get him drunker so that he’ll talk, but Luke just falls asleep. Lady Audley comes to give Luke his extortion money, but when she sees Robert and Luke together, she decides to set fire to the inn to silence both of them. She sends Phoebe back to Audley Court while she sets fire to Mt. Stanning. Alicia intercepts them on the road to Audley Court with the news that Sir Michael has suffered a fit. Phoebe sees Mt. Stanning burning, and intuits Lady Audley’s role in it when Lady Audley tries to prevent her from returning. Robert intercepts the abduction Lady Audley is trying to carry out. He denounces her as a murderess, and a dying Luke shows up to corroborate his story. Then Alicia shows up to say her father is dead. Then George shows up to say that he is alive. Then Luke dies and Lady Audley goes mad.