In the year 2153 of the Gregorian calendar, a meteorite fell on the Southern Continent, directly killing tens of millions of people, and triggering earthquakes and tsunamis that affected hundreds of millions of people around the world. After the disaster, the Alpha Empire, the world's largest country, organized its army to take over the southern continent and carry out rescue operations. To commemorate this unprecedented disaster, later generations named 2153 in the Gregorian calendar as the first year of the fall, and the area directly affected by the fall disaster was called Tukanunan.
19 Years after the fall, some residents of Tukanunan and military personnel who participated in disaster rescue suffered physical mutations and even died. After research, the Alpha Empire discovered that the falling meteorite emitted a huge amount of unknown radiation. As soon as the news came out, a large number of residents of the Southern Continent began to migrate to other continents, triggering a huge flow of refugees and affecting all countries. In response to the emergency, the Alpha Empire took the lead in establishing a blockade area to inspect, isolate and treat refugees. Because the blockade surrounds Tukanunan like a huge ring on the planet, the blockade is also called the "ring".
74 Years after the fall, a major explosion occurred in the 17th District of the Star Circle, and one third of Nosong Town was razed to the ground. In order to rescue the victims and investigate the truth of the explosion, Lin Yun, the commander-in-chief of the 17th District, sent an elite team to Nuosong Town to investigate. However, what he didn't expect was that a mysterious organization gradually surfaced in the explosion. This mysterious organization not only stirs up Tukanunan, who is gradually calming down, but also unveils a corner of a conspiracy that will eventually affect the fate of everyone in the world.
