Saikin, Imouto no Yousu ga Chotto Okashiinda ga.

Mitsuki Kanzaki struggles to adjust after her mother’s remarriage gives her a new home and a stepbrother, Yuya. Her situation becomes stranger when a ghost named Hiyori possesses her and refuses to leave.

Hiyori claims that unresolved feelings for Yuya prevent her from reaching the afterlife. Mitsuki must cope with an unwanted presence and the misunderstandings it creates, while learning how to relate to the family she has barely begun to accept.