The isolated village of Tohoku is surrounded by high mountains, and has a tradition that only the eldest sons may marry and inherit. The filthy, unshaven younger sons, called yakkos, work the land and never have sex. To redress an ancestor's crime, the widow Oei has to take each yakko for a night. However she refuses to take Risuke, who has particularly vile breath. So Risuke's eldest brother Tasuke tells his wife Asa to take Risuke for a night, while an old blabbermouth suggests another alternative to Risuke.