The film consists of re-edited material from the original television series Ultraman. Episodes 1, 8, 26, and 27 were used for the film. They were narrated by Hikari Urano as an "Ultraman Documentary". Allegedly only one new scene was shot, and that some parts of the movie where shot in black and white for unknown reasons. The movie screened at the same time as the Toho movie King Kong Escapes.
Takatora Kureshima (Kamen Rider Zangetsu) visits a former Yggdrasill Corporation experimental project site located in the poverty and conflict stricken Republic of Torukia. He is visiting the site for the first time in 8 years, and is suddenly attacked! Suprised he stumble and falls into a giant hole which leads into an underground city. This underground city is the most dangerous place in the republic, in which many young men are killed defending themselves while trying to survive. These men use Lock Seeds and Drivers to transform into Armored Riders. Due to the fall Takatora has lost his memory. He is helped by the leader of Team Orange Ride. Unbeknownst to them, there are cameras hidden all around the underground city. The ones behind the cameras are responsible for the conflicts in the city. One man in particular is seeking revenge on Takatora for a specific reason...
After the battle against Zogu was over, both Gamu and Fujimiya began to live normal lives until another threat arrives on Earth - a surviving monster soldier of Zogu's army named Gakuzom.
At the turn of the century, all of the Earth's monsters have been rounded up and kept safely on Monsterland. Chaos erupts when a race of she-aliens known as the Kilaaks unleash the monsters across the world.
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 WWII, Germans obtain the immortal heart of Frankenstein's monster and transport it to Japan to prevent it being seized by the Allies. Kept in a Hiroshima laboratory, it is seeming lost when the United States destroys the city with the atomic bomb. Years later a wild boy is discovered wandering the streets of the city alone, born of the immortal heart.
An expedition in the South Pacific lands on a tropical island where the natives worship the mysterious deity Gappa. An earthquake opens up an underground cavern and a baby reptile is discovered inside. The natives warn the foreigners to leave the hatching alone, but they don't listen and take it back to a zoo in Japan. Soon after, moma and papa Gappa start smashing Tokyo looking for their kidnapped child.
Japan is thrown into a panic after several ships are sunk near Odo Island. An expedition to the island led by Dr. Kyohei Yamane soon discover something far more devastating than imagined in the form of a 50 meter tall monster whom the natives call Gojira. Now the monster begins a rampage that threatens to destroy not only Japan, but the rest of the world as well.
Two fishing scout pilots make a horrifying discovery when they encounter a second Godzilla alongside a new monster named Anguirus. Without the weapon that killed the original, authorities attempt to lure Godzilla away from the mainland. But Anguirus soon arrives and the two monsters make their way towards Osaka as Japan braces for tragedy.
After a fishing boat is attacked, the sole surviving crew member realizes it is none other than a resurrected Godzilla. However, efforts to bring the story to light are suppressed by the Japanese government amid growing political tensions between the United States and the Soviet Union, who are both willing to bomb Japan to stop the monster.
Egos kidnaps the children of Information Supervisor Sakaguchi, Yoko and Kenichi. They then blackmail him into stealing the blueprints and completion status of the Battle Fever robo. Tetsuzan Shogun, who joined the Defense Department at the same time as Sakaguchi, is greatly concerned and confronts him. Sakaguchi escapes but vows to make amends. He appears at Egos factory, where they too are building a giant robo, and discloses a false timetable. When Egos orders them killed, Sakaguchi reveals dynamite strapped to his body. He backs away with his children and gets them to safety. He then returns to the factory, and blows himself up to destroy it. Unfortunately, his sacrifice is in vain, as their evil robo is already completed. But Battle Fever’s giant robo is also complete and ready to save the day!