A film adaptation of the short story of the same name by Guy de Maupassant. The action takes place in the XIX century. Franco-Prussian War of 1870. A group of French bourgeois leaves in a stagecoach from Rouen occupied by Prussian troops. Along with them comes one attractive demimonde lady. The only way to get out is to persuade her, nicknamed "Ball-of-Fat" a la "Boule-de-Suif" to satisfy the lust of the head of the gendarmerie...