Since the first words appeared in human civilization, the great human civilization has been inherited and developed a splendid culture. But this universe is not born for human beings, and human civilization is destined to encounter one after another Asteroid impacts, gamma ray bursts, encounters with malicious alien civilizations, and gravitational disturbances of other stars lead to changes in the orbit of the earth...There are countless challenges that may be encountered, and...as long as human beings exist Human beings will encounter these things after a long enough time. The story begins on an ordinary day. On this day, people suddenly find that the sun is dimmed... Human civilization is about to encounter the first time since entering the civilization era. challenge.