I became close with my classmate's girlfriend and finally succeeded in confessing my feelings and starting a relationship. She was a beautiful girl popular at school, the perfect partner for me. But suddenly, my little sister Kurara confessed to me. She honestly told me she loved me and insisted we start dating. Truthfully, I'd had adolescent fantasies about her myself. Her pure feelings shook my heart, leading me to make a decision. Here begins a forbidden romance between brother and sister—an intensely passionate, borderline extreme experience of erotic thrills and loving affection. She sincerely whispers, "Big brother... I'll give myself to you completely◆," as their bond grows ever deeper.