A girl named Mitsuki Kanzaki lives with her step-brother Yuya after her mother remarries. One day, Mitsuki is possessed by the self-proclaimed spirit of a young girl, Hiyori Kotobuki. Hiyori (in Mitsuki's body) must fall in love with Yuya to move toward the "Gates of Heaven."
Source: MyAnimeList [Link]
Producers: Project No. 9
Official Website: http://imocyo-anime.com/