In the future world, mankind has experienced a disaster called the "Great Silence", a historical fault, and almost all the technological and civilizational achievements of the old era have been lost. The survivors rebuild civilization in a giant city called New Babel. The city is divided into three classes: the elites of the "Sky Dome District" who live on the top floors and enjoy a clean environment and high technology; the citizens of the "Corridor District" who live in the middle layer and maintain the operation of the city; and the scavengers of the "Abyss District" who live on the ground floor and are invisible to the sun and make a living by recycling "relics" from the old era. The entire society is strictly controlled by the giant enterprise "Eternal Era", which not only monopolizes technology, but also compiles and publishes the only "official history"
