A French village during the Franco-Prussian War of 1870–1871 becomes the setting for a severe trial faced by the elderly widow Mother Sauvage. Her only son is away at the front, while four young Prussian soldiers are quartered in her isolated home. Their forced coexistence reveals the conflict between ordinary human sympathy and the merciless logic of war. The story examines maternal love, loss, revenge, and the moral choice of a person deprived of what mattered most.