In the romance comedy, 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 towards the "Gates of Heaven."

Recently, My Sister is Unusual (最近、妹のようすがちょっとおかしいんだが。, Saikin, Imōto no Yōsu ga Chotto Okaishiin Da Ga. , lit. "Lately, My Little Sister's Been Acting A Bit Strange, But."), also known as ImoCho (妹ちょ。), is a Japanese manga series by Mari Matsuzawa, serialized in Fujimi Shobo's Monthly Dragon Age since November 9, 2010. An anime television series adaptation is scheduled to air from January 2014. It will also be adapted into a light novel written by Kougetsu Mikazuki, published on January 18, 2014 under Fujimi Shobo's Fujimi Fantasia Bunko imprint.  A live action film adaptation will premiere in the spring of 2014.