Saikin, Imouto no Yousu ga Chotto Okashiinda ga.
Kanzaki Mitsuki lives with her step-brother Yuuya after her mother remarries. One day, Mitsuki is possessed by the self-proclaimed spirit of a young girl, Kotobuki Hiyori. Hiyori (in Mitsuki`s body) must fall in love with Yuuya to move towards the Gates of Heaven.