In 1992 (only several months after the battle between Godzilla and Mecha-King Ghidorah), the United Nations form the U.N.G.C.C. (United Nations Godzilla Countermeasures Center). After declaring their first counter-Godzilla weapon, the air-ship Garuda, a failure, the U.N.G.C.C. recover the remains of Mecha-King Ghidorah from the ocean and convert the 23rd century armor and other components to create the ultimate weapon: Mechagodzilla. By 1994, two years after its construction began (and 40 years after Godzilla first attacked Japan), the giant robot is compleated and prepared for action.
Meanwhile, on an expedition to an irradiated island called Adonoa in the Berring Sea, a Japanese team comes across a gigantic nest containing two large eggs, one hatched and one still intact. They remove the unhatched egg from the nest and bring it to their camp for further study. However, their actions are being observed by the former occupent of the second egg: Rodan, a giant Pteranodon. The mutated pterosaur attacks the scientific team in an attempt to protect its unborn kin. As the team flee from their destroyed camp, they notice that the sea is begining to glow blue and, several seconds later, Godzilla rises and lumbers ashore. Rodan violently attacks the King of the Monsters, pecking at him and razing him with his sharp tallons and spiked chest. While the two ancient beasts fight, the team quickly secures the intact egg and escape on board a helecopter. On the ground, Rodan is defeated by Godzilla and aparentely killed. Godzilla then turns his tail and begins to pursue the helecopter, and the egg, back to Japan. Once there, the unhatched egg (presumed to contain another pteranodon) is brought to Kyoto to be monitered and studied. There, a strange vine-like plant found growing on the shell is descovered to contain a strange kind of psychic music. When it is played, the egg begins to hatch, and from out of the fractured shell emerges not a baby pteranodon, but a Baby Godzilla. Professor Omae, one of the scientists who dicovered the egg on Adonoa Island, speculates that the Godzillasaurus (the un-irradiated dinosaur species that gave rise to Godzilla himself) are animals that lay their eggs in the nests of other dinosaurs, thus explaining the presence of a Godzillasaurus egg in the nest of a Pteranodon. Unfourtunately, no sooner has the Baby Godzilla pushed its self from it's egg then the adult Godzilla appears off the coast of Japan, heading toward Kyoto with great spead. At the U.N.G.C.C. headquarters, the G-Force (the military arm of the U.N.G.C.C.) scramble and prepare Mechagodzilla for battle. The 120 meter tall mechanical monster is launched from it's underground base and quickly flies towards Godzilla. Once it lands, it begins to unleash a barrage of weapons against it's organic counterpart, including a Mega-Buster beam, a powerful Plasma Laser system, and shock cables designed to pierce Godzilla's hide to deliver a powerful electric shock. However, when these are fired into Godzilla during the battle, theatomic titan unleashes a nuclear pulse that sends the energy flying back towards it's source. The violent influx of energy begins to send Mechagodzilla's systems haywire, and the machine's engine room soon erupts into flames. With the robot paralyzed, the crew can only watch helplessly as Godzilla rises and shoves them aside. With it's mechanical doppelganger defeated, the Monster King heads once again toward Kyoto, destroying everything in it's path. It soon arrives at the science institute where the Baby is located. However, the scientists within had previously realized that Godzilla had come to Japan to find it's newborn kin, and had taken the infant to the basement of the building in an attempt to isolate it from the adult monster. The plan works, and Godzilla, sad and angry, is forced to leave, unable to locate the young Godzillasaurus.
Soon after, the U.N.G.C.C. places the Baby Godzilla in a specially-built enclosure at their H.Q., the G-Center, for safe keeping. There, the dinosaur is studied and X-rayed. However, after analyzing the X-rays, the scientists at G-Center discover something unexpected: the Baby has a large muscle-like organ, or "sacral brain", in it's hip, presumably used to control lower body functions. The U.N.G.C.C.'s top brass, the Counter G Bureau, assume that the adult Godzilla, being the same species as Baby (albiet much more heavily mutated), must also posess such a "second" brain. Armed with this new information, the Bureau, along with the G-Force Commander Aso, develop a new plan of action. They plan to outfit Mechagodzilla with a new weapon: The G-Crusher System. The system will be designed to fire high-powered cables into Godzilla's sacral brain and deliver an electric shock powerful enough to destroy it. This, it is hoped, will paralyze Godzilla's lower half and make it impossible for him to stand on his own two feet. The conflict, the Bureau decides, will take place on the uninhabited Ogasawara Islands, far from any city. However, in order to lure the nuclear behemoth to the desired location, U.N.G.C.C. Director Segawa and Comander Aso decide to use the Baby Godzilla as a decoy, as the Monster King had previously displayed an ability (and willingness) to persue and locate the younger monster. Although protests arise from both Baby's human guardian, Asuza Gojo (whom Baby had imprinted on both before and after his hatching), and psychic Miki Saegusa (who had also grown quite attached to the young kaiju as well), the plan goes ahead and Baby is loaded into a canister to be flown, via helicopter, to the site of the opperation. However, the complete success of said opperation is not in the books. Unknown to the U.N.G.C.C.'s top brass, an incident had previously occured that would place the entire plan in jeopardy. A few days earlier, Miki had brought a group of young students from the Psyonics Center (where she had previously been a student(See Godzilla vs Biollante)) to visit Baby. Once their, the young girls sang a song for him... the same song that had eminated from the mysterious plant that had grown on Baby's eggshell. Upon hearing the melody, Baby suddenly turned very violent, roaring and slaming his body against the fence around his enclosure. Miki surmised that the music from the plant, when played, gives any creature that the plant has effected (in this case, Baby as it had grown on his egg) a boost of power and of energy. Unfortunately, Baby was not the only monster to recieve energy from the ancient plant's song. Back on Adanoa Island, under a pile of rocks and debris, the eyes of Rodan flicker open as the creature regaines consiousness. Realizing that it's "brother" had been taken away, the prehistoric reptile spreads it's huge wings and, as the energy granted to it by the plant's music flowed through it's body, transforms into a new, crimson-shaded, nuclear-powered, form: Fire Rodan. The huge pterosaur then departes the island and flies to the aid of it's "sibling".
Back in Japan, the J.S.D.F. helicopter transporting the canister that contains both the Baby Godzilla and his guardian Asuza heads toward the Ogasawara Islands. Suddenly, Fire Rodan drops out of the sky and destroys the helicopter, grabs the canister in his talons, and promptly flies off towards the coast of Japan. In an instant, the U.N.G.C.C.'s plan has completely disintigrated, and the G-Force is forced to launch Mechagodzilla in an attempt to intercept Rodan. Also launched is the U.N.G.C.C.' first counter-Godzilla mech: Garuda. At the same time the G-Crusher system was being integrated into Mechagodzilla, both the giant robot and it's airship predecessor were upgraded to literally combine into one, powerful machine dubbed Super Mechagodzilla. By nightfall, Rodan arives in Tokyo, and Mechagodzilla is not far behind. Not long after the flying reptile lands, it begins to break open the container with it's sharp beak in an attempt to reach the Baby Godzilla inside. Fortunately, Mechagodzilla lands and prepairs to confront Rodan. However, the latter had no intention of surrendering it's only family and unleashed it's new Uranium Heat Beam (an energy beam similar to Godzilla's famous Atomic Ray) apon the former. Mechagodzilla quickly retaliates and the two titans exchange energy beams. After a few minuites, Garuda arives and pursues Fire Rodan through the air above the city. Unfortunately, a flyby and strike from Rodan's chest spikes quickly sends the aerial mech crashing to the ground. Mechagodzilla soon retaliates and blasts Rodan out of the sky and into a building. As the huge robot approaches the downed reptile, Rodan suddenly rises and begins to violently peck at Mechagodzilla's eyes, successfully pecking one out of commision. However, with a blast of the immense machine's Plasma Laser Cannon, Fire Rodan is sent flying backwards into a group of buildings, where it lies with a huge bleeding wound in it's chest, unconscious and both foaming and bleeding from the mouth.
Away from the battle, a team of soldiers work to free Baby and Asuza from the canister. As they attempt to cut open the door, the sea behind them begins to stir, and a few moments later, Godzilla rises and lumbers into the city. Mechagodzilla turns around and quickly fires it's Mega Buster beam at the creature that, having successfully followed the bait, was now at the robot's mercy. Godzilla, too, fires his beam, and the two energy rays meet between the two monsters. The beams then explode and push the monster back a little ways. Godzilla then charges and grabs his mechanical clone by the head, picks it up, and throws it down again. As the nuclear leviathan begins to pummel Mechagodzilla with his tail, Garuda finally reenters the fray, firing at Godzilla and distracting it long enough to allow his downed opponent time to escape. With Godzilla distracted, Garuda flies into position behind Mechagodzilla and attaches to its back; Super Mechagodzilla is born. The robot monster, now much more maneuverable than before, fires tranquilizer missiles into it's organic counterpart, and the crew prepares the G-Crusher. On board, Miki Saegusa uses her psychic powers to sucessfully locate Godzilla's sacral brain. However, she cannot find the strength to fire the electric cables into the creature whom, through her relationship with Baby, she has come to care about. Her orders, however, are clear, and she reluctantly locks on to the brain and fires the cables. They soar through the air and shoot through Godzilla's thick hide. With the cables in place, Miki places her hand on the button, and fires. A powerful electric current shoots through the cable and into Godzilla's second brain. Miki watches as the organ explodes and the King of the Monsters, paralyzed from the waist down, falls to the ground in agony. Mechagodzilla begins to blast Godzilla with beam after beam, and continues to send a current through the cable into the beast. The atomic saurian lets out one last feeble roar, and the lays motionless on the ground. Godzilla, it appears, is dead.
Back near the canister, the soldiers are still attempting to cut out Asuza and the Baby Godzilla. However, after Godzilla's final roar and apparent defeat, Baby begins to slam himself against the door, eventually breaking through it completely. The young Baby Godzilla then lets out the loudest roar it can make, and the sound travels across the battle field to a fallen ally. From under a pile of rubble, Fire Rodan calls back feebly and lifts it's self from the ground, attempting to fly to it's distressed "brother". Mechagodzilla, however, has no intention of letting the pterosaur escape and quickly and easily shoots it down. Rodan lands on Godzilla's colossal corpse, and it appears that the two monsters will lie dead together. However, the flying monster has one last trick to play. As it lays its head on Godzilla's spines, a glowing powder-like substance begins to fall around the fallen Monster King. Inside Mechagodzilla, Miki realizes that Rodan is transferring his life energy to Godzilla. She watches her screen in amazement as Godzilla's sacral brain begins to heal itself. Outside, Rodan's body disappears as it sacrifices itself so that its "sibling" might live. Several seconds later, Godzilla's eyes open, and the creature rises again. With energy swarming around him, he lets out a roar of triumph. Mechagodzilla, however, is in trouble. The unbelievable amount of energy released by Rodan has started to melt the metal monster's beam-proof diamond shield. With the robot now defenseless, Godzilla unleashes a new weapon: Spiral Fire Ray (a special gift from Fire Rodan) upon Mechagodzilla. The machine falls to the ground and, after a few more hits from the new ray, erupts into flames. Godzilla roars in victory; Mechagodzilla has been defeated. Real life has triumphed over artificial life.
Meanwhile, a helecopter has arived to take the soldiers and Asuza to safety. Baby, however, cannot come along. Asuza knows that Godzilla will never stop seeking the young dinosaur, and that as long as he remains with people, he will be used like an asset, a decoy in another plot to kill Godzilla. She apologizes to him and says goodby as she leaves him on the ground. A few minutes later, the adult Godzilla finally locates the Baby and stands before him, towering bbove the tiny creature. Baby, his eyes glowing red with fear, runs behind the canister to hide. Back at Mechagodzilla's wreckage, the crew has survived and escaped the burning robot. Miki receives a call from Asuza, who pleads with her to somehow help Baby realize that he must go with Godzilla. Miki accepts and uses her powers to send the plant music to Baby, whom calms down and finally comes out of hiding to stand before his new "father", who has a very gentle look in his normally hostile eyes. With that, both monsters turn and head out to sea, their future beyond anyone's guess.
The film sold approximately 3,800,000 tickets in Japan.
- Released: February 8, 2005
- Aspect Ratio: Widescreen (1.78:1) anamorphic
- Sound: Japanese (2.0), English (2.0)
- Supplements: Trailers for Godzilla: Tokyo S.O.S., Mirror Mask, Anacondas: The Hunt for the Blood Orchid, and Steamboy
- Note: The subtitles for the Japanese track are really 'dubtitles', or subtitles that follow the dubbed version of the film, rather than the original Japanese.
- The original ending for Godzilla vs. Mechagodzilla II was that Mechagodzilla killed Godzilla, therefore ending the VS series. But, Godzilla transfers his energy to Baby Godzilla who grows into an adult Godzilla. This new Godzilla would be used in Tristar's version but Sony decided that they wanted to make a standalone film of their own. Instead, the scenario was used two years later in Godzilla vs. Destoroyah.
- Another ending considered is that Godzilla is killed by Mechagodzilla, but not after damaging the ship Garuda. The nuclear engine inside irradiates Godzilla, giving him new strength to defeat his mechanical clone.
- In the release of the international dub of the movie they referred to Rodan as his Japanese pronunciation, Radon.
- The airship Garuda is named after a Japanese mythical bird spirit.
- Keiko Imamura and Sayaka Osawa, who portrayed the Cosmos in the previous year's Godzilla vs. Mothra, appear in this film as the teachers at the Psyonics Institute. Director Takao Okawara included an in-joke by having the two speak in unison like the Cosmos, but this confused many people when they saw the movie.
- This film, the 5th of the Heisei series, is the 3rd film of the series to include a monster that utalized Rodan's roar, although this is the only one of those three films to actually include Rodan himself. The monsters that used the roar prior to Rodan's appearence in this film include: Godzillasaurus (slowed down, have also Gamera's roar); King Ghidorah/Mecha-King Ghidorah (sped up and altered in pitch); and Battra (slightly altered).
- In an interesting (but probably unintentional) parallel to the original Godzilla, when Rodan pecks out Mechagodzilla's right eye, and the eye goes black, the giant robot bears an uncanny resembalence to the one-eyed Dr. Serizawa, who's right eye was lost in battle in WWII.
- The Godzilla suit used predominantly in this film has been nicknamed "RadoGoji".
- Rodan's role was originally filled by Titanosaurus, but he was replaced 2 weeks before the film was released.