Have you ever thought about it - some people "fall" from the world suddenly.
Not dead. One morning, no one remembered him. His photo is still there, his name is still there, but no one knows who it is anymore.
There is a bell underground. Every time it rings, one person is erased in this way.
Gu Zhao could hear the bell.
Therefore, he knows before others who will "disappear" tomorrow.
He tried to bring those who were about to be erased back into the world. But he found that the more he stayed, the faster he became empty - people around him began to be unable to call his name, could not remember his face, and finally forgot that "this person existed".
And the bell has rung six times.
The seventh time, it still rings.