After losing her beloved husband, mother Arisa took in his son, Takashi, and lived a quiet life. One day, she met Sato at work, who proposed to her. Desperate to escape her financial struggles, Arisa positively accepted his offer. However, Takashi strongly opposed it, insisting, "It should just be Mom and me," causing a rift in their family bond. Arisa's relationship with Sato deepened day by day, and the two frequently indulged in passionate affairs. Witnessing this up close, Takashi became captivated by his mother's voluptuous body. Torn between jealousy and an abnormal desire, he began to harbor forbidden lust for her. The hidden impulses and inner conflicts within this household set the stage for a shocking new development.