After realizing that Kyoichi was rejected by his childhood friend Shizuna, his little sister Momoko decides to take things into her own hands and take him for herself. However, in an effort to prevent the siblings from getting too friendly with one another, Shizuna offers Kyoichi an opportunity to teach her in the ways of sex. With both girls vying for his attention, Kyoichi cannot help but reciprocate their feelings.
