In a certain period in the future, due to abnormal geological activities, volcanic earthquakes will erupt frequently on the earth, and volcanic ash will cover the sky and the sun, causing a devastating blow to the global ecology. Moreover, due to the release of energy within the Earth, its stable state in the solar system was destroyed, and the Earth's trajectory became farther away from the sun. Although this is a slow process, humans had to deal with it very early.
In short, everything has completely changed.
Purpose: Cherish life