Riko Shinohara, a pure and innocent, simple, slightly plump beautiful girl, makes her first appearance at Fitch! She can't bring herself to like her mother's new husband, so she lives with him as a new family member, but she doesn't talk much to her stepfather and tries to keep him at a distance. One day, when she is tired from cheerleading practice and takes a nap on the veranda, her stepfather appears and starts licking her lips. However, this incident was just the beginning of the many nightmares that will befall her from now on...