Kouichi Sakakibara returns to Yomiyama North Junior High after a month-long sick leave, joining class 3-3. There, he becomes intrigued by Mei Misaki, a mysterious girl with an eyepatch whom he met in the hospital. Strangely, no one acknowledges her existence, warning him to stay away from "things that do not exist." Despite their warnings, Kouichi befriends Mei and learns of a dark curse tied to the class. As tragedies unfold, he embarks on a quest to uncover the truth behind the curse, but doing so comes with terrifying consequences. The mystery proves deadly for those involved.