A School Frozen in Time Vol. 3 (Kodansha, 2021)

First, there were eight, and now there are six. With Mitsuru and Shimizu now missing, everyone is on edge as they try to find a way out of their horrifying circumstances. The remaining students continue to suspect that the person keeping them trapped is among them, but Shimizu also suggested a bizarre, new theory: they may be inside the mind of the person who took their own life at the school festival. Takano thinks he might just know who their tormentor is, but many unanswered questions still remain. Can he get to the bottom of this mystery before his time's up?