Set in the aftermath of the fourth film, the series focuses on 11‑year‑old Keisuke Amano, Natsume"s younger brother (both children of Keita Amano and Fumika Kodama from the original Youkai Watch anime) who remains unconvinced by any supernatural occurrences. However, when he notices his sister often returning home late, he starts following her and soon learns that she is performing exorcisms on malevolent Youkai together with friends Touma and Akinori, while also managing a Yo‑Kai detective agency. Once their hidden work is revealed to him, Natsume agrees to accompany her on investigations of Youkai crimes and confrontations with evil spirits, ensuring peace throughout the city. The narrative unfolds as they navigate complex cases that test their resolve and friendship.
