Synopsis 

       In 2030, humanity faced a new virus. It came from a type of parasite found in the dust in the air. These parasites live inside hosts and can control living beings, similar to zombies in movies. Infected creatures become biologically deformed monsters that survive by eating and reproducing rapidly. We call it "PD-30" (Parasite Dust-2030), or simply “PD.” At that time, the Federation of Nations (FN) established certified aseptic zones. People who were not infected were relocated to these zones, which were located underneath North America, stretching from the United States to Canada. Five years later, PD had been studied extensively, and a special forces unit was formed. These elite combat teams were organized by country to eliminate the PD threat.