Ordinary housewife Masami lives with her husband Kenji, who harbors sexual dissatisfaction. As their intimate life gradually diminishes, Masami grows increasingly frustrated. One day, her husband's former boss, Oshima, pays a visit. He reveals that Kenji once borrowed money from him, shocking Masami. Oshima then demands repayment through sex. Tempted beyond resistance, Masami crosses the line—despite overwhelming guilt, she writhes in ecstasy under Oshima's passionate advances.