An ancient dinosaur of immense strength, Anguirus was secretly released by the alien race known as the Xiliens. The spiked carapace of the leathery behemoth crashed through downtown Shanghai, China. Thousands were killed, and the news of this dreadful assault spread far and wide. The Earth Defense Force released its aerial warship Karyu to repel the assault. While powerful, Karyu was ultimately no match for Anguirus. In a stunning twist of fate, however, the monster suddenly vanished!

The Xiliens fooled humankind into believing that Anguirus was gone. Several other monsters, which had also assaulted the world's cities simultaneous to Anguirus' attack, were also declared annihilated by the duplicitous alien race. Though their intentions seemed noble, their true goals were soon uncovered. It so happened that the Xiliens were planning world domination! As these new allegations were coming to light, Anguirus was released yet again on Shanghai. Karyu was again summoned, but the battleship was sent crashing into the Capitol, killing those unfortunate people within.

The Xiliens' plans were soon turned upside down, though, when an invulnerable juggernaut was released from its icy crypt in the Antarctic. Godzilla was heading for Tokyo, and the Xiliens began to throw monsters in the creature's way to halt his progress. Anguirus, along with Rodan and King Caesar, attacked Godzilla at Mt. Fuji. When the aggressive ankylosaur charged, Godzilla merely stomped his head to the ground. This was followed by the slam of his tail, sending Anguirus soaring into the sky and ultimately knocking Rodan out of the air. King Caesar proceeded to kick Anguirus like a soccer ball. Godzilla moved into a defensive position, but the spiked ball turned at the last second and ended up toppling onto the unconscious Rodan. Following King Caesar's defeat, all three of Godzilla's opponents found themselves stacked on top of one another. Godzilla roared in triumph, and continued his trek to Tokyo.