Yui and Mitsuki are half-sisters. The mother of the two is very poor, and the three also have to pay the debt left by the father. One day, the mother of the two said that she would remarry, although she was a little old, but she could pay off the debt to her parents. Although they felt suspicious, when they saw their mother's happy smile for a long time, the two agreed. And then they were able to live the rich life they had always wanted. But after a while, the two realized the true nature of their stepfather. Every time his mother wasn't there, he would repeatedly rape the sisters and threaten to kick them all three away if he dared to reveal this...