While her husband is away on a business trip, Rumiko Hiyoshi is suddenly attacked by her stepson Yoshio. Though she desperately resists at first, her body gradually responds to his relentless arousal, until she is completely dominated and forced to swear herself as his "bitch." With her husband gone, Yoshio's rampage begins. He brings in his friends who take turns using her body, dragging her into a brutal gang rape. Initially resisting, she slowly succumbs, sinking deeper into depravity as she becomes a sex slave and cumdump for the group of young men.