Seiko is unsatisfied with her relationship with her husband. As if reading her inner turmoil, her stepson Yoshio begins to seduce her. Tempted by his words and despite knowing it's wrong, she gives in to her uncontrollable desires. Yoshio's demands grow increasingly intense, and while her husband is away on a business trip, he invites his friends over to dominate Seiko. Gradually, she is pulled deeper into their web, crossing a point of no return.