In Saikin, Imouto no Yousu ga Chotto Okashiinda ga., a family embarks on a delicate journey of reconciliation. Mitsuki Kanzaki, a high school freshman, grapples with the arrival of her new stepfamily following a tumultuous past. Unexpectedly, an accident leads Mitsuki to be possessed by the lovelorn ghost of Hiyori Kotobuki, fixated on Mitsuki's stepbrother Yuuya. To help Hiyori move on, Mitsuki must navigate the challenges of sharing her body with this amorous spirit. As she confronts her deep-rooted distrust and adjusts to her unconventional circumstances, will Mitsuki find a way to fulfill Hiyori's unrequited love for Yuuya and confront her own hidden emotions?