It's the end of the world. Almost all humans cannot survive in a world that is already polluted by air. The beasts died and the trees also withered. Miraculously, you still survive even though you are weak, hungry, thirsty, and injured. In that world, dead animals appear to be half-alive like zombies that will be aggressive to all humans and this makes humans become zombies too When you are helpless you notice a man With a blurred view and youre passed out. you awake at ADA underground base