When Mt. Otake erupts, the director of the Information Science Center, Shinpei Muraki, travels to the area to observe the phenomenon first hand. While conducting his studies, he sees a woman who is quickly fleeing the area. Muraki offers his assistance to the woman in escaping from the danger zone. She accepts and identifies herself as Akikuko Inamura, daughter of physicist Dr. Inamura. Returning to his lab with Akikuko, Muraki develops the rolls of film which he took of Mt. Otake's eruption, and much to his surprise, discovers a dinosaur like silhouette in the flames. Akikuko goes to Dr. Inamura's lab accompanied by Muraki and Dr. Radner, a nuclear physicist, to show her father the photos and discuss what their implications maybe. As they arrive, the group witnesses two men attempting to abduct Dr. Inamura; fortunately, when Muraki and Radner confront the two they quickly flee. Radner and Inamura suspect that the attempted kidnapping is due to Inamura's "Reiconium," a substance possessing a kind of super nuclear energy. Dr. Inamura explains that "Reiconium" maybe used as fuel for a new generation of safe nuclear power plants; consequently, it is also viable as a weapon containing several times the destructive power of modern nuclear weapons.

Shortly afterwards, reports come in that several people have sighted a dinosaur like creature resembling an ape near Lake Saiwa. Muraki has a book of mythology that identifies this Kajiu as the Enjin Reijuu, the Ape God Beast. Coincidentally at a distance of 50 meters from the lake, another monster appears, this one reptilian in shape which legend calls Mizu Reijuu, the Water God Beast. Akikuko examines the photos which Muraki took at Mt. Otake and discovers that the creature seen at the eruption is actually Doragon Reijuu, the Dragon God Beast. According legend the three different beasts are actually incarnations of a single Kajiu called Bagan.

Meanwhile, somewhere in the Pacffic Ocean, a freighter is illegally dumping nuclear waste into the ocean until a unexplained disaster occurs, sinking the ship. Since their whereabouts' were supposed to be secret, no distress signal is sent out. Several members of the crew survive and manage to take refuge in a weird cave located on a neighboring island. Unfortunately most of the men are killed by carnivorous plants and giant ticks called Shokilas. A sole survivor by the name of Tagami manages to escape the island and tell local islanders the story. The islanders believe that what the crew found wasn't a cave at all but actually part of Godzilla's body. Upon hearing the story Dr. Inamura and his associates decide to investigate the nuclear waste processing plant that Tagami confessed was involved in the illegal dumping.

Upon arriving at the seaside facility, Dr. Inamura is ambushed by the same two men who had previously tried to kidnap him at his laboratory. But as they lead Inamura to their secretly docked submarine the sky suddenly grows dark and a deafening sound like thunder fills the air. The men realize that the sky hasn't grown dark, but what they are staring at is actually the lower body of a creature, just as Godzilla lets out a terrifying roar. The kidnappers flee once again upon seeing Godzilla. It is noted that Godzilla has been consuming the illegally dumped nuclear waste and was able to trace it back to its source. Godzilla then starts to consume nuclear energy at the nuclear waste processing plant growing even stronger.

Meanwhile, in the Northern Alps the Japanese SDF launches an attack against Enjin Reijuu. Missiles, tanks, rockets, and artillery are all used against the creature. Enjin Reijuu retreats into a tunnel in the side of a mountain causing the mountain to collapse. Then suddenly Doragon Reijuu emerges from beneath the collapsed mountain, and immediately takes flight. The SDF pursues Doragon Reijuu with a squadron of fighter jets. The jets injury the beast, but are unfortunately destroyed during the confrontation. The injured Doragon Reijuu crashes into the ocean. Once in the water the beast transforms into the Mizu Reijuu and it is discovered that when Bagan changes shape it also heals itself.

After the failure of conventional weapons against the monster, the SDF decide that its time to release several "super weapons" that they have been developing. The SDF sends out Giant Basu which is equipped with a giant arm able to capture submariners. With it are the VTOL fighters which are special craft capable of vertical take off and landing. Joing them is the Super Beetle, a vehicle that has excellent underwater mobility. The "super weapons" are joined by a fleet of submarines and battle cruisers as they search for Mizu Reijuu. The beast is eventually spotted, and torpedoes are fired and the creature, injuring it as well as severing one of it's arms. The victory is short lived how ever, as a tidal wave destroys the fleet as Godzilla arrives. Mizu Reijuu leaps out of the water at Godzilla changing into Doragon Reijuu. Godzilla quickly dispatches the creature by shooting it with his atomic breath, causing Doragon Reijuu to fall back into the sea. It changes back to Mizu Reijuu, and then once again to Doragon Reijuu and in the process heals its wounds. The creature once again attacks Godzilla, but this time the Super Beetle interrupts the fight, but only to be destroyed and the two Kajiu continue there fight. Doragon Reijuu lands on a nearby mountain top, and transforms itself into Enjin Reijuu. The creature continues to attack Godzilla, this time by grabbing boulders off the mountain and throwing them at Godzilla. After several direct hits Godzilla collapses in the water, and Enjin Reijuu disappears into the mountain.

Eventually Godzilla manages to rise out of the water and he slowly heads in the direction of the Kanto Nuclear Power Plant. Upon reaching the power plant, Godzilla attacks the reactor building, demolishing it. The monster then lowers it's head into the ruins of, and it's body begins to glow, sparking with blue white energy. He quickly absorbs the energy and then heads toward the Mount Fuji seeking Enjin Reijuu. Upon finding the creature Godzilla attacks it, and with his renewed energy quickly over powers the creature. The creature changes shape to the Doragon Reijuu form and continues its attack on Godzilla. Godzilla blasts both of the monsters wings causing it to fall into the sea, and then the creature begins a different kind of transformation. From the chest of Doragon Reijuu, the arms, legs, and face of the Mizu Reijuu begin to form, then the arms, legs, and face of the Enjin Reijuu also take shape on Doragon Reijuu's body. Bagan's true form is revealed, however once Bagan is in this form he can not change out of it, and as a result can no longer heal himself. Godzilla makes quick work of Bagan's new form, and Bagan dies falling into the sea.

Godzilla destroys an oil field, and then disappears into the sea. When Godzilla reappears in Izu, it is feared that Godzilla will next attack Tokyo. With its "super weapons" destroyed the SDF has no choice but to ask Dr. Inamura to use his Reiconium against Godzilla. Inamura refuses stating that its potential as a weapon out weights that of destroying Godzilla.

Meanwhile, Akikuko is traveling to her family's cottage in the Hakone area. While riding on a ropeway up towards the cottage the power in the area is suddenly interrupted due Godzilla approaching the area. Muraki realizes that Akikuko maybe in danger, so he joins a helicopter rescue mission sent into the area in a attempt to rescue her. The team is unable to rescue everyone from the ropeway so the helicopter departs leaving behind Muraki and Akikuko among others. As the helicopter takes off, it is suddenly blasted from the sky by Godzilla. Threatened by the monster's presence, the couple manages to find a hang glider and escape from the area. The couple returns to Dr. Inamura' s laboratory, where Akikuko begs her father to use the Reiconium against Godzilla,and finally Dr. Inamura agrees.

The Reiconium weapon is readied and placed in a trap baited with radioactive fuel on the remote Beonase Atoll. The bait lures Godzilla to the area, but the weapon malfunctions. Dr. Radner volunteers to go onto the atoll to repair the damage before Godzilla gets away. Dr. Radner is successful in repairing the device but is crushed by Godzilla shortly after making the neccasary repairs. Before Godzilla can escape Dr. Inamura activates the Reiconium device and Godzilla is engulfed by a blue-white flame as nuclear fusion begins inside his body. The Kajiu falls into the sea, as the surface is rocked by an enormous explosion. Dr. Inamura is convinced that his weapon has worked and tells his daughter that even though Dr. Radner was not able to die on his own time. As long as I live I shall fight for peace in this Nuclear Age.

Several months later, Godzilla's body floats ashore on the west coast of the United States, next to the beach is a nuclear power plant, and shortly after washing ashore Godzilla's eyes open and he lets loose a earth shattering roar.

This project is noteworthy for a variety of reasons. Foremost though is because it introduces Bagan, the most famous lost creation of all time, whose failed carrier would spread across a decade and a half. Another reason is the great transition that the script went through before it went in front of the camera 4 years later. Almost the entire script was scrapped with the exception of the lead characters being left behind after a helicopter rescue and Godzilla's hunger for nuclear material. Also this is the most developed script for a Lost Project, it was done even down to the narration and credit sequence as the title 'The Return of Godzilla' was supposed to flash across the screen at the end of the movie.

Ultimately though the script is still rather rough, human interaction is rather dry and mimics that seen in the first Godzilla too much. One can not complain about the monster cast though, as seeing this many in a Heisei film would have truly been a treat. Of course the idea of the SDF's 'Super Weapons' was very undeveloped, what's the point of introducing them if there only purpose is to be quickly destroyed along with conventional weapons? Also the anti-climax to the film is also a downfall, unlike the final script for 'The Return of Godzilla' which quickly wraps the story up after Godzilla destroys the Super-X, this one continues going as Bagan dies about 2/3 the way through the movie.

Overall the idea was very lavish, but probably too much so as the reason for the script being brough back to the drawing board was beacuse Tanaka couldn't get the finacing for such a project.

The initial concept was pitched in 1980, and was constructed by Akira Murao and Tomoyuki Tanaka. Much later, in 1984, the first draft of the 30th anniversary Godzilla film by Tomoyuki Tanaka and Shuichi Nagahara still retained the title, although dropped this concept. Eventually, it was revisied and the title changed to simply "Godzilla", although "The Return of Godzilla" would end up being used as the International title to the production.

Note, the name Sokunikusu was not the Kajiu's official name, as the creature was unnamed when the project was canned. Also no picture of Bagan (1st Generation) exists beyond a concept art drawing for the script. The above picture of him was done through the Toho Kingdom's interpretation of the concept drawing, using it as a model and then coloring it in and fleshing it out a bit.