An alien civilization from another world, the Xiliens appeared to be a peaceful, helpful, and familiar people. These humanoid beings seemingly repelled an infestation of monsters that plagued the planet, and they revealed that they planned to save the Earth from an incoming asteroid. The truth was far more sinister than these visitors from abroad cared to disclose. For they weren't as human as they appeared. Each individual alien was in an amazingly realistic disguise, and beneath this facade, the revolting heads of a deadly people peered through their crafty costumes. After all, these evil beings could be accepted far more easily when taking on a pleasing form...

However, Captain Gordon had grown suspicious of the true intentions of the Xiliens, and at a news conference with the leaders of this extra terrestrial race, he planned to get to the bottom of their schemes. A shot was fired at a Xilien troop, and his body opened to reveal his true identity. The body was taken into the middle of the interview, and the world was shown the real form of the aliens. Another shot was fired, and another alien was uncovered. The Xilien leader was suddenly fired upon by his second-in-command, and the true intent of their arrival was revealed: domination! The new leader of the Xiliens escaped, and upon returning to the Mothership, he released an army of savage monsters on the world once more, for these creatures had always been under the Xilien command! With destruction and conquest on their minds, the Xiliens attacked human civilization in full force!

A race of highly intelligent beings from a distant star, the Xiliens desired to dominate the planet Earth. In order to prove themselves as allies to humankind, they devised a cunning plan. A militia of monsters was released, and this army of anomalous animals began to ravage the planet's major cities. The Xiliens suddenly abducted the monsters, and made it appear as though they had destroyed these towering titans. The Xiliens also found another method by which to fool the world: humanlike disguises. Surely, humankind would be more apt to accept familiar faces than the true, grotesque forms of this alien race. When they revealed their plans to the world, their intentions appeared simple and pure, for they wanted to save humankind from an asteroid that was plummeting toward the helpless planet. Some people, however, suspected that the Xiliens' assistance to humankind was too good to be true. During a press conference, Captain Gordon and his men continued to search for the truth, and uncovered the Xiliens as frauds. The Xilien leader was assassinated by his second in command, and the monsters were unleashed on the planet once more.

Luckily, a small group of humans managed to formulate a plan for a counteroffensive. The soaring battle cruiser, called the Gotengo, was sent to Antarctica to release Godzilla from his icy tomb. The determined dinosaur pounded his way through wave after wave of Xilien resistance, all in the form of monsters. Finally, the Gotengo led Godzilla into Tokyo, and the powerful aircraft infiltrated the Xilien Mothership. The alien leader was defeated after a long battle, and in retribution, he set the ship to self-destruct. The humans managed to escape, but the unlucky Xiliens were vaporized in an immense explosion. With the Xilien forces finally annihilated, the Earth was able to breathe a sigh of relief. It would live to see another day.