Hiram Bent, a St. Louis hat dealer, goes to Paris with his conservative, prudish wife. At a fashion show, Madame Claire fails to interest them and sends for Fifi, a particularly successful model and saleswoman who makes a large sale and wins Hiram's admiration. While delivering a hat to the fiancée of Étienne Du Beauvray, Fifi complains to an officer (actually Étienne) about his horse destroying the hat; so Fifi is forced to improvise a hat for Marianne. Later, Étienne meets Fifi at the salon, and a romance develops. Impressed by her sales ability, Bent buys out Madame Claire and establishes Fifi as "Mademoiselle Modiste." Étienne, suspicious of ent's activities, challenges him to a duel, but the misunderstanding is soon cleared up and Fifi is happily united with Étienne.