Despite her son being right there, wife Rin continues a lewd affair with her husband. Her actions intensely excite her pubescent son, and before long, he begins seeing his mother as a woman. As this situation persists, the mother, unable to suppress her own desires, seduces her son, and the two impulsively become intimate. From then on, even with the father present at home, the son constantly craves his mother's body, staying up late into the night, running wild through the house. These impulsive acts destabilize the family's balance, giving rise to a new, forbidden relationship.