French nuclear tests irradiate an iguana into a giant monster that viciously attacks freighter ships in the Pacific Ocean. A team of experts, including Niko Tatopoulos, conclude that the oversized reptile is the culprit. Before long, the giant lizard is loose in Manhattan as the US military races to destroy the monster before it reproduces and it's spawn takes over the world.

A mysterious extraterrestrial being resembling Godzilla rapidly approaches Earth. The monster, dubbed SpaceGodzilla, lands to challenge the King of the Monsters.

The advertising director of Pacific Pharmaceuticals, frustrated with the low ratings of their sponsored TV program, seeks a more sensationalist approach. He orders his staff to Faro Island to capture King Kong for exploitation. As Godzilla re-emerges, a media frenzy generates with Pacific looking to capitalize off of the ultimate battle.

Journalists Ichiro Sakai and Junko cover the wreckage of a typhoon when an enormous egg is found and claimed by greedy entrepreneurs. Mothra's fairies arrive and are aided by the journalists in a plea for its return. As their requests are denied, Godzilla arises near Nagoya and the people of Infant Island must decide if they are willing to answer Japan's own pleas for help.

After a meteorite unleashes a three-headed beast upon Tokyo, Mothra tries to unite with Godzilla and Rodan to battle the extraterrestrial threat.

Searching for his brother, Ryota stows away on a boat belonging to a criminal alongside two other teenagers. The group shipwrecks on Letchi island and discover the Infant Island natives have been enslaved by a terrorist organization controlling a crustacean monster. Finding a sleeping Godzilla, they decide to awaken him to defeat the terrorists and liberate the natives.

During an assignment, foreign correspondent Steve Martin spends a layover in Tokyo and is caught amid the rampage of an unstoppable prehistoric monster the Japanese call 'Godzilla'. The only hope for both Japan and the world lies on a secret weapon, which may prove more destructive than the monster itself.