The current earth is also known as the city of division. Half of the Earth, as seen by Nebula, is thriving, full of tranquility and peace. The other half has been invaded by a doomsday crisis, and is full of cruel and bloodthirsty monsters. It is like a hell, almost uninhabited. The two divided worlds are called the "prosperous age" and the "troubled age" respectively. The two sides are distinct and separated by many obstacles.
The story is divided into a line of prosperous times and a line of troubled times.
The prosperous age line has two male protagonists, 2257 and Nebula (in the early stage, they are roughly gentle and reliable in attack and cold and arrogant in love), and they are slow to develop. Everyone is very busy.
The troubled times line is the female main line and may have bg elements. But the heroine is also very busy.
At first, the seemingly boring and meaningless daily killing of monsters gradually tears away the peaceful appearance covering daily life under the constant intersection of the two lines, revealing the ugly and mottled reality. The protagonist and his group move in the same direction as the story develops, heading towards an unknown ending...
Intent: human beings