The Seventh Person Disappeared

There is an abandoned clock tower in the old coastal city "Egret Town". Twelve years ago, seven high school students met to play a "truth game" in the bell tower. A fire destroyed the bell tower that night. One of them died, one disappeared, and the remaining five went their separate ways. Twelve years later, they received the same text message one after another: You were missing one person back then. Sender's signature: The seventh person.