The rich and aristocratic Lydia Languish's head has been turned by the many romantic novels she has read. Because of this reading, she refuses to marry anyone of her own rank or wealth. She fixes her ideas on marrying a common soldier and chooses the poor ensign Beverley.

Ensign Beverley is, however, really the aristocratic and wealthy Jack Absolute, son of Sir Anthony Absolute. He describes himself as poor and common because he knows this is the only way he will persuade Lydia to marry him.

Events come to a head when Sir Anthony arranges for Jack to marry Lydia. When Lydia finds out that the supposedly impoverished Ensign Beverley is really the wealthy Captain Absolute, she has a fit and refuses to marry him. Jack is in a dilemma until he enters a duel with Sir Lucius O’Trigger. When Lydia learns that Jack risked his life in a duel, she suddenly reevaluates him as suitably romantic and thus worthy of her love.

There is high comedy in the fact that Lydia would want to reject Jack, even though she loves him, for qualities—wealth and status—that most people would find highly desirable. Lydia is an example of a person who almost throws happiness away with both hands by living in fantasyland, a theme picked up by a number of writers in the nineteenth century.