Mitsuki (Tenka Hashimoto) and Yuya (Yukichi Kobayashi) turned into step sister and stepbrother because of their parents' union. Mitsuki can't get along with her new family and Yuya doesn't know how to approach his step sister. 1 day, Mitsuki becomes possessed by the soul of Hiyori (Mayu). Hiyori thinks Yuya can help her get to heaven and likes Yuya. Hiyori puts a leather chastity belt upon on Mitsuki and a plan carries spot to help ship Hiyori to heaven.