Mitsuki (Tenka Hashimoto) and Yuya (Yukichi Kobayashi) eventually become step sister and stepbrother because of the parents' union. Mitsuki can not get along with her new family and Yuya does not understand just how to approach his new step sister. One afternoon, Mitsuki becomes possessed by the spirit of Hiyori (Mayu). Yuya is liked by hiyori and considers Yuya will help her get to heaven. A leather chastity belt is placed by hiyori upon on Mitsuki and a plan takes spot to help ship Hiyori.