Mashita Fumie, 40 years old. She thought her relationship with her son would be a one-time thing, but her teenage son keeps initiating intimacy again and again. Every time her husband leaves the house, her son starts lasciviously caressing her back and buttocks. Each time, she grows more anxious, wondering what would happen if her husband found out—yet she succumbs to her uncontrollable desires. As days pass, her bond with her son deepens further. These warm, passion-filled moments continue to shake her heart.