The prestigious all-girls school, St. Catherine Academy, is a home to beautiful girls from rich heiresses to sports elites who enjoy a peaceful campus life. However, there is a hidden hierarchy system, with the lowly janitor, Genshu Yamashita, reigning at the top. Even the beautiful principal is at the bottom of this caste system, dedicated to serving those above her. As a new school year begins, Yamashita starts searching for new targets, with the aim of training them as sex slaves by exploiting their weaknesses.