Lucy gets clothes and other items for helping—or pretending to help—those around her. She acts as a go-between for Lydia and Captain Jack Absolute, who is pretending to be a mere ensign so Lydia will return his affections. However, Lucy betrays the lovers to Mrs. Malaprop so she can get money from her as well.

Mrs. Malaprop is furious with Lydia for planning to elope with a poor man. Jack’s father, Sir Anthony, who doesn’t realize his son has been wooing Lydia under a false identity, goes to Mrs. Malaprop and proposes Jack as a match for her niece. Mrs. Malaprop has been trying to get Lydia to accept Acres as a suitor, but she won’t hear of it. Mrs. Malaprop agrees to Sir Anthony’s suggestion, thinking Lydia might be more willing to accept Jack than Acres. This sets in motion conflict between father and son because Jack doesn’t realize at first that Lydia is the girl Sir Anthony is ordering him to marry.

After Mrs. Malaprop dismisses Acres as a suitor for her niece, Lucy—who has been accepting letters from Acres but not delivering them—does him what she calls “a last friendly office” by telling him his rival, “Ensign Beverly,” has been in Bath before him. Acres tells all this to Sir Lucius O’Trigger, who encourages him to challenge Beverly to a duel. Since Acres doesn’t use Lydia’s name when telling the story, Sir Lucius doesn’t realize the young lady in question is the same one he thinks is responding passionately to his love letters. He’s been giving the letters to Lucy to deliver to Lydia, but Lucy has been giving them to Mrs. Malaprop, who thinks they are for her and is answering them under an assumed name. All this leads to a lot of confusion during the attempted duel that ends the play.