"Your mom is really beautiful," his friend said, and Masaru began to think of his mother as a woman. One night, Masaru's mother, Miho, invited her husband to have sex, but was turned down. Her uncontrollable sexual desire led her to masturbate next to her husband. Masaru happened to wake up and saw Miho masturbating, which made him start to see his mother as a woman. When Masaru's father went away on a business trip, he took the opportunity to tell Miho how he felt over and over again. Overflowing with desire and feelings, Masaru and Miho had sex when their father was about to return home and they were alone at home.