Xu Wang is the only doctor in Wushan Town and the last person who is still "awake".
Three years ago, a white fog of unknown origin enveloped the entire town. From that day on, the people in the town began to gradually forget. They forget their names, the way home, and the people they love deeply. In the end, it becomes a zombie-like "echo" that only repeats the behavior of the last day of his life.
The postman delivers letters day after day that are never opened. The grocery store proprietress wiped the empty counter over and over again. They are Xu Wang's patients, as well as his former neighbors and friends.
Everyone who tried to leave the town disappeared at the end of the thick fog and never came back.
