In 2125, the ozone layer ruptured at an accelerated pace, surface air pressure rose sharply, and oxygen content plummeted. The world entered an era of high pressure and low oxygen, which people called the "end of the earth." Humanity began to build underground dome cities on a large scale. When the earth was swallowed by high-pressure and low-oxygen gray rain, humans hid in underground domes to survive. A conspiracy in the name of "evolution" had already quietly spun a web.
