A plague started spreading in Japan...a plague so strong that even a whiff of it can cause you to hallucinate and die.  Humanity thought that wearing face masks would make it but those that died before them turned into horrible-looking mutants.  These mutants, can spread continuous diseases and they eat from living humans and turn them to mutants.  The plague has been taken care of but now zombies are multiplying into hordes, animals getting bitten starts to mutilate and increase in size and