In 2230, a contagious and highly contagious virus suddenly appeared in the world, infecting most of the world in a short period of time. Immediately after the solar flare broke out, the virus mutated under the strong radiation, and the infected people turned into zombies. Governments in various places were caught off guard. Even if they sent troops to try to stop it, they eventually collapsed. Each place was also controlled by small local armed forces. The survivors lived in the ruins after the war, trying to rebuild their homes while resisting the attacks of zombies.
