The older sister Miru is a bright and lively female college student, while the younger sister Shion is a quiet and reserved schoolgirl. The two sisters were known in the neighborhood as beautiful sisters. The mother, who lost her husband early in life, remarried and got a new stepfather. Then the mother became pregnant and decided to give birth at her parents' house to be on the safe side. When the mother was gone, the stepfather changed completely and began to look at the sisters with lewd eyes... "Without your mother, you sisters are just women..." Miru and Shion were brainwashed by their stepfather and became addicted to his insatiable cock.