Nene Yashiro, still bound to the ghost Hanako-kun at Kamome Academy, dives deeper into the school's supernatural world alongside exorcist-in-training Kou Minamoto. The boundary between the near shore of the living and the far shore of apparitions has begun to waver. The Clock Keepers, apparitions who regulate the flow of time within the school, draw the trio into a crisis that challenges Hanako's authority as the Seventh Mystery.