Mitsuki (Tenka Hashimoto) and Yuya (Yukichi Kobayashi) become stepsister and stepbrother because of the parents' union. Mitsuki can not get together with her new family and Yuya doesn't understand how to approach his new stepsister. One day, Mitsuki becomes owned by the soul of Hiyori (Mayu). Hiyori considers Yuya can help her access to paradise and likes Yuya. Hiyori puts a leather chastity belt upon on Mitsuki and also a plan takes spot to help ship Hiyori to paradise.