Eight years ago, my father remarried and I and Riho became siblings. - We're not related by b**, but we've become a family. - For a happy family. - But... before I knew it, I had become aware of my younger sister as a woman. - I was scared to be with him. - I'm sure one day I'll become aroused by my younger sister. - So I ran away from my sister. - Using my busy university life as an excuse, I had escaped from my desires, and before I knew it, I hadn't returned home for a year. - During that time, Riho was raped by her father...