The Shadows of Who We Once Were Vol. 7 (Kodansha, 2022)

Twenty-seven former classmates of Shinozuka Elementary School have gathered for a reunion only to find themselves being locked in the old school building. The man behind this crime is none other than Mikio Yumesaki, with a goal to test the goodness in humanity. On the second day of the tragic experimentation, the students are greeted by the last morning of their confinement. Hidden among the young girls and boys is a cold-blooded murderer...Until the truth is revealed, until that ""evil"" is punished, they will not stop doubting each other. Threatened at gunpoint, using fear as a tool, ""he"" desperately searches for the truth. How much blood must be shed before it finally ends?