Eating Dust in the Last Days

The red moon comes, the end of the world begins, and the sun disappears behind the horizon. . But it has not risen yet. Humanity, which has been plunged into darkness, has ended an era and created a new era. And the human beings who were sealed in the old era wake up in the new era, with familiar and unfamiliar memories. How can we find the truth of the end of the world in this new era, and where will the fate of mankind ultimately go? The protagonist is a locksmith in the new era, but he wakes up a hundred years after the end of the world. How should he try to live in this world that was once very familiar but is now unfamiliar?