- Her older sister, Himari, who is an honor student, and her younger sister, Hinako, who can't fit in at school and doesn't go to school. The two lived peacefully with their mother and her remarried father-in-law, a wealthy man. However, when her mother is in the hospital for childbirth, the house becomes a space of pure lust dominated by her father-in-law. - Skillfully take advantage of Hinako's inferiority complex and vaginal shot. Sexual intercourse using Himari's kindness to think of her sister ... Before I knew it, the two had become sex slaves competing for their father-in-law's and competing for service. - Her mind and body are dominated so much that she is conceived while enjoying which one gets pregnant first.