The spaceship AAB-Gamma is dispatched from FAFC headquarters in Japan to make a landing on the planet Mars and investigate reports of UFOs in the area. As they near the red planet, they encounter a mysterious UFO that coats the ship's hull with unusual spores. Taking one of the specimens back to earth, it soon develops and grows into a giant chicken-lizard-alien monster that tramples Japan.
As Japan is preparing to host the Olympics, a gang member wanting to go to America is sought after by the police after helping his friend conduct a robbery.
Though he has come from a rough background on the streets, Muraki quickly rises through the ranks by means of his well-honed blackmailing instincts. Desperate to keep rolling with his freewheeling lifestyle, Muraki sees his luck begin to crumble when he sets his sights on the business partners of a powerful gang boss.
