Ako Togawa and her boyfriend Hiroki were enjoying their youth in high school. They visited their childhood friend Yoshio at his casting press factory. After the death of his father, Yoshio gave up high school but continued to study for college. Yoshio envied Hiroki for dating Ako because Ako was Yoshio's secret love since childhood. One day, three of them agreed to study together in Yoshio's room. While waiting for Hiroki who were coming late, Ako fell asleep. As he peeped at Ako's white panties, Yoshio lost control and took Ako. During her resistance, Ako hit her head and lost conscious. When she woke up, Ako's hands and feet were tied with rope. That was the beginning of her life as a pet of Yoshio. How long will the days of love, desire and confinement alone behind the door last...?
