After losing her husband at a young age, Miki sought to ease her loneliness through repeated affairs. Her son Kazuya was aware of this, and he also understood that Miki desired physical closeness with him. Whenever she bathed or masturbated, Miki would leave the door slightly open, allowing Kazuya to peek in on her. One day, Kazuya suddenly embraced Miki. She happily accepted his advance.