When a top secret chemical compound called MW infects an island near Okinawa, the military is sent in to kill all the victims and cover up the incident. A survivor named Michio Yuki grows up to become a highly-successful banker, but he is slowly being driven mad by the effects of MW. After committing a series of ruthless crimes to get revenge against the people responsible for the cover-up, he decides that the only way to truly get revenge is to unleash MW on the world and exterminate the entire human race.