Yumi, who married an older man she once worked under, suffered from ongoing sexual dissatisfaction after marriage. Burdened by intense sexual frustration, her life took a turn when Seiichi, her husband's son from a previous relationship, became captivated by her allure and took her for himself. Drawn to each other, the two began a secret, intimate relationship under the same roof, meeting daily in passionate encounters that pulled them deeper into emotional turmoil. One morning, her husband caught them in the act. Reacting instantly, Yumi grabbed Seiichi's hand and fled the house. That impulsive decision would drastically alter the course of her life forever.