When the son comes home from school, he finds his mother, Asahi, sleeping in a defenseless state. His mother sleeps in a sloppy state with her panties completely exposed. It is not surprising that a son of his age would feel disgusted by the sight, but the panties visible from the well-proportioned body of a married woman are seductive, and the sweat running down her body is more than enough to drive the son crazy. The son's reason breaks down at the sight of his mother sleeping defenselessly, never dreaming that it would arouse his son's lust. He turns into a wild beast and attacks her.