Mizuki and I are not actually siblings. We met when we were students, as we were both children from different generations when our parents remarried. A few years later, our parents died in an accident, and we lived together, supporting each other. As we continued living together, I began to fall in love with Mizuki. My dream of spending time with Mizuki like this was snatched away by my best friend, Kyohei. Kyohei, who had feelings for Mizuki, was jealous of our relationship, and when I was not around, he got close to Mizuki...