An 11-year old girl named Satsuki Miyanoshita moves with her little brother Keiichirou, her father Reiichirou and her pet cat Kaya to the hometown of her deceased mother, Kayako. On their first day of school, Kaya enters the old school building. When Satsuki and Keiichirou go after him, they met Hajime Aoyama, Leo Kakinoki and a sixth grader named Momoko Koigakubo.They soon discover that the old school building is haunted by many ghosts.The gang eventually meet a demon named Amanojaku, that tries to attack them. Later, they find a diary that once belonged to Satsuki's mother. With the help of the diary, Satsuki discovers how to exorcise Amanojaku. After they do it, they discover that Amanojaku was trapped in Satsuki's pet cat, Kaya. Now, they must discover how to make Kaya return to normal and exorcise the many ghosts that reside in the old school building.