During an outing of the college archeology club, Kana and her boyfriend Reiji find the dead body of an ancient bishop, frozen in meditation. A weird pattern of stones spread out around him and Kana accidentally breaks the pattern, thus freeing a hundred evil spirits. Then, Reiji hears the voice of the bishop's spirit, who has been containing the evil spirits for hundreds of years. Reiji and Kana are given the task of re-containing the evil spirits. And to ensure their support, the bishop puts a curse on them: Reiji will turn into a horse during the day, and Kana will turn into a hawk during the night. The lovers will not be able to meet in human form until all the evil spirits are contained again.