The story is set in the Franco-Prussian War and follows a group of French residents of Rouen, recently occupied by the Prussian army. The ten travellers decide for various reasons to leave Rouen and flee to Le Havre in a stagecoach. Sharing the carriage are Boule de Suif or "Butterball" (lit. suet dumpling, also translated as ball of fat), a prostitute whose real name is Elisabeth Rousset; the strict Democrat Cornudet; a shop-owning couple from the petty bourgeoisie, M. and Mme. Loiseau; a wealthy upper-bourgeoisie factory-owner and his wife, M. and Mme. Carré-Lamadon; the Comte and Comtesse of Bréville; and two nuns. Thus, the carriage constitutes a microcosm of French society, representing different parts of the French population during the late 19th century.