In 2089, a mysterious phenomenon called a "void" suddenly appeared on the earth. The void will continue to expand, swallowing everything around it. The area eroded by the void hole is called the "virtual zone", and the creatures in it will mutate and become murderous "phantoms".
Humanity is retreating steadily, retreating to the "safe zone" protected by the "quantum shield". Outside the safe zone, there is an endless virtual area and wandering shadows.
