A scientific expedition on a remote island finds fossilized pteranodon remains and an intact giant egg. As they prepare to ship it to Japan, Rodan swoops down and destroys the encampment. Godzilla rises from the ocean and the two beasts taunt each other. While they battle, the humans escape on a helicopter with the egg.
The egg is taken to Kyoto for study. Kazuma Aoka, who is in a Mechagodzilla training program, checks out the egg as a pteranodon enthusiast, but is run off by Azusa, one of the researchers. Several days later, the egg hatches! Instead of a flying dinosaur as expected, a cute little (6 foot) baby Godzillasaur emerges and becomes attached to Azusa.
Following the path of the egg, Godzilla arrives near Kyoto. G-Force deploys Mechagodzilla.. They face off in a wooded hilly area. The metal monster blasts at Godzilla with several types of energy weapons, with little effect. Godzilla uses his nuclear fire against Mechagodzilla, but it just sheds off the diamond skin like water on a waxed car hood. Using a “Plasma Grenade” beam, the robot knocks Godzilla to the ground. More weapons are used against the felled giant, who writhes in pain. Just as it appears Mechagodzilla is going to defeat Godzilla, a malfunction immobilizes the robot. Godzilla continues his march to Kyoto, swatting away the conventional forces sent against him. Azusa and Kazuma suspect the baby dinosaur may be calling to Godzilla. When the King of the Monsters arrives at the building with Godzillasaur, he turns and leaves.
Repairs are being affected to Mechagodzilla. Meanwhile, Kazuma is performing maintenance on Garuda, a flying battle tank that was superseded by the robot. Officials decide to use the friendly monster to lure Godzilla into a trap.
Recovered from his wounds, Rodan flies in causing extensive damage. He apparently is also hearing the call of the Godzillasaur. The giant pteranodon grabs the container with “Baby” and and Azusa inside and leaves.
With repairs attached, Mechagodzilla is deployed against Rodan, with Garuda deployed separately. Rodan is attempting to break open the container with the Godzillasaur when the two machines arrive. Garuda distracts Rodan, which forces Garuda to crash into a building. Mechagodzilla blasts at the flying monster with its Plasma Grenade, knocking it out the sky.
As Rodan lies bleeding profusely, a team from G-Force attempts to free the baby and Azusa from the container. Godzilla rises from the bay and again faces Mechagodzilla. The blast at each other with fire from their mouths. Godzilla stumbles, but renews his attack against a damaged Mechagodzilla. He picks it up, tosses it aside, and slams at it with his tail.
Kazuma has managed to repair Garuda and presses an assault against Godzilla. While he is distracted, Mechagodzilla uses a flying tackle to knock over the beast. With Godzilla lying stunned, Garuda attaches to the back of Mechagodzilla. Together they form Super Mechagodzilla, and continue their attack.
They advance against Godzilla, firing most the beam weapons simultaneously. The Plasma Grenade, now recharged, is used and knocks him down again. He rises again, only to be shot with a new weapon called the G-Crusher. It launches two spikes with power lines attached into Godzilla’s body. Incredible jolts of electricity are fired through the lines, causing him excruciating pain.
The Godzillasaur breaks out of the container and cries out. It awakens Rodan, who flies to Godzilla, only to be shot down by Mechagodzilla. It falls onto the King of the Monsters, but its life energy is transferred into Godzilla, who rises again with renewed strength. The same energy that brought Godzilla back to life also weakens the robot’s armor. Godzilla blasts at it again and again. Mechagodzilla lies broken and burning. The crew escapes.
With her heart breaking, Azusa flies off in a helicopter, leaving behind the Godzillasaur. The smaller monster swims off with the giant.
Human Cast: Masahiro Takashima (Kazuma Aoki), Ryoko Sano (Azusa Gojo), Megumi Odaka (Miki Saegusa)
Monster Cast: Godzilla, Mechagodzilla, Rodan, baby Godzillasaur
LogBook entry by Robert Parson