- Keiko Imamura as Cosmo #1
- Sayaka Osawa as Meru Ozawa, Cosmo #2
- Towako Kimijima as Prof. Chinatsu Gondo
- Akira Nakao as General Takaki Aso
- Masahiro Takashima as Major Sho Kuroki
- Yasufumi Hayashi as Kenichi Yamane
- Yuta Mochizuki as Yamato Tribe Prince Geki/TyrannoRanger
- Seiju Umon as Sharma Tribe Knight Goushi/Mammothranger
- Hideki Fujiwara as Etoph Tribe Knight Dan/Triceraranger
- Takumi Hashimoto as Daim Tribe Knight Dan/Tigerranger
- Reiko Chiba as Risha Tribe Princess Mei/Pteraranger
- Eiji Maruyama as the voices of Daizyujin/Goryujin/Ultimate Daizyujin
Since 1996, both Miki Saegusa and Meru Ozawa of the "United Nations Godzilla Countermeasures Center" ("U.N.G.C.C." or G-Force for short) have been keeping taps on Godzilla Junior, who after nearly dying in "Godzilla vs. Destroyer", has now fully grown into the new King of the Monsters. Also helping is Kenichi Yamane, who had returned to college and managed to get a doctorate.
The year is now 1999 - in which the Cosmos fortold of a large meteorite coming to Earth, destroying - Mothra is currently still in space, hoping to divert the meteorite, as she had promised Battra. Meanwhile on Earth, Godzilla Junior has been spending most of his time in the sea, sleeping. Miki and her friends are in a wooded area when she begins to sense something - something she never sensed before. They feel the ground rumble beneath their feet and see two sillouttes of giant creatures. At first they think it's Godzilla Junior, but are surprised to see instead two Tyrannosauruses.
Then suddenly a young teenager comes up and tells the Rexes not to harm them. Miki senses some intelligence in the beasts as they comply. Meru asks the boy's name and tells them that he's Satoshi. Kenichi is fascinated to see two actual living T-rexes and he asks Satoshi where they came from. Upon learning the adults are of G-Force, Satoshi warns them not to take the Rexes away as they are the only living dinosaurs left on Earth and explains that they were given to him as eggs from a group of people known as the Zyurangers when he was a little boy in 1992.
Up in space, Mothra finally finds the meteorite and begins her plan to divert it from its course to Earth. Unfortunately, it contains the evil of Dai Satan, the ultimate evil in the universe. Not even Mothra's power can compete with it, so Mothra sends the Cosmos back to Earth, knowing she wouldn't survive. Satoshi just about finishes telling his story about the Zyurangers' final battle against Bandora and her master, Dai Satan, when the Cosmos return. Miki eagerly asks how Mothra is, but senses something is wrong.
The Cosmos explain to their human friends that the meteorite contains the essense of Dai Satan. Upon returning to G-Force, Miki and her crew bring the Cosmos who explain the story of the Zyurangers and Dai Satan more clearly, as seen in flashback -
All of this started 170 million years ago. It was the era of the dinosaurs, but actually humans existed as well. They were an ancient race of Dinosaur-evolved Humans (Kyoryu Jinrui). These ancient humans separated into five tribes (Yamato, Sharma, Etoph, Daim and Risha), each of which had a dinosaur as its Guadian Beast (Shugoju). They had good fortune and lived in peace. But then the Witch Bandora (Majo Bandora) (formally the Queen of the Fairy Tribe Dall, after having her son Kai killed by a T-rex after he smashed its eggs, sold her sole to Dai Satan) appeared and attempted to wipe out humanity and turn the Earth into a wasteland. Her minions were Grifforzer (Guriffoza), Lamie (Ramii) (who could become the giant Lamie-Scorpion (Rami Sukopion)), Totpat (Tottopatto), Bukbak (Bukkbakku), Pleprechuan (Puripurikan), and her grunts were the Golem Soldiers (Goremu Hei).
Many knights lost their families. However, saviours appeared before them - the Guardian Beasts of each tribe. The Guardian Beast Tyrannosaurus (Shugoju Tiranozaurusu) for the Yamato Tribe; the Guardian Beast ZyuMammoth (Shugoju JuManmosu) for the Sharma Tribe; the Guardian Beast Triceratops (Shuguju Torikeratopusu) for the Etoph Tribe; the Guardian Beast SaberTiger (Shugoju SaberuTaiga) for the Daim Tribe; and the Guardian Beast Pteranodon (Shugoju Puteranodon) for the Risha Tribe. The Witch Bandora was finally captured and the Guardian Beasts banished her to planet Nemesis until some careless astronauts broke her seal in 1992. However, the tribes chose five warriors to be put into a long sleep in case Bandora ever returned - these being the Yamato Tribe Prince Geki/Tyrannoranger (Yamato Zoku Purensu Geki/Tiranorenja), the Sharma Tribe Knight Goushi/Mammothranger (Shama Zoku Naito Goshi/Manmosurenja), the Etoph Tribe Knight Dan/Triceraranger (Etofu Zoku Naito Dan/Torikerarenja), the Daim Tribe Knight Boi/Tigerranger (Daimu Zoku Naito Boi/Taigarenja), and the Risha Tribe Princess Mei/Pteraranger (Rishiya Zoku Purencesu Mei/Puterarenja) - who were watched over by the Mysterious Sage Barza (Fushigi Sennin Baza). From there, the Kyoryu Sentai Zyurangers were born.
After recieving the Legendary Weapons (Densetsu no Buki) (Tyrannoranger's Ryuugekiken (Ryugekiken) sword, Mammothranger's Mothbreaker (Mosubureika) axe, Triceraranger's Tricelance (Torikeransu), Tigerranger's Saber Daggers (Saberu Daga), and Pteraranger's Ptera Arrow (Putera Aro)) from the Land of Despair, and discovering the secret of Daizyujin (Daijujin) - the combined form of the five Guardian Beasts, the Zyurangers soon learn of a sixth warrior - the Yamato Tribe Warrior Burai/Dragonranger (Yamato Zoku Senshi Burai/Doragonrenja), who was in fact Geki's older brother, and of Geki's true heritage. He and Burai were the sons of the Black Knight. When Burai was 8 and Geki was 1 year old, the Yamato King was without a male heir and the King would only spare the disrespectful Black Knight from execution if he turned Geki over to the King. The Black Knight later lead a revolt against the Yamato King - revealing that he really turned Geki over so he would have an excuse to overthrow the King.
Upon seeing his father's death at the hands of the King, Burai vowed to avenge him. After stealing the Yamato Dragon Armor (Yamato Doragon Ama) treasure, he took refuge in the Land of the Elves, planning to use the armor to one day have his revenge on the King. But when the war against Bandora killed the King, it ruined Burai's chance for revenge and blamed everything on his own brother, Geki. He asked Gnome to put him in suspended animation in the Secret Mountain. After being awakened, he attacked the Zyurangers, and upon retrieving the Demon Sword Hellfiende (Maken Hellfiede), ended up working for Bandora for a short period. After being given his own Legendary Weapon, the Zyusouken (Jusoken), he summoned the Guardian Beast Dragon Caesar (Shugoju Doragon Shiza) and wreaked havoc on Tokyo, until Geki managed to snap Burai out of his anger, destroying the Hellfiende, and making him the Zyurangers' 6th member. The Guardian Beasts then showed another combo, in Gouryujin (Goryujin) (combined form of Caesar, ZyuMammoth, Triceratops and SaberTiger). But after the Beast Cavalry God King Brachion (Jukishin Kingu Burakion) appeared, Burai would let them know that his life-force would give away so long as he stayed away from his Lapseless Room. During his long sleep there had been an earthquake, in which boulders fell from the roof and crushed Burai, killing him. But Daizyujin had the Spirit of Life Clotho (Inochi no Seirei Kuroto) set Burai a lifespan. Eventually Burai died, giving Geki his Dragon Armor and Zyusouken so they could still use Dragon Caesar.
Eventually, through the Guardian Beasts' combined/original form, Ultimate Daizyujin (Kyukyoku Daijujin), the Zyurangers managed to defeat Bandora, sealing her and her minions away again, and with Barza, left to join the Guardian Beasts in heaven.
Flashback over, the Cosmos reveal that the meteorite that contains Dai Satan's essense has destroyed Mothra. Then Prof. Gondo gets the idea to have the Cosmos try and summon the spirits of the Zyurangers, hoping that maybe the Guardian Beasts can help. The Cosmos agree, and say that with Daizyujin's power, they might be able to stop the meteorite. Suddenly the navy spies Godzilla Junior raising up from the sea. The Cosmos then teleport themselves and Miki and Meru to the Guardian Beasts' altar, praying to the Dinosaur Gods for help.
Godzilla reaches the shore and looks up as the sky lits up. The meteorite has entered Earth's atmosphere, but instead of destroying Earth completely, the meteorite changes into the spiritual face of Dai Satan who claims Godzilla's body as his own. Instantly, Godzilla's behavior changes dramatically into a savage beast (much like the original Godzilla) that wants nothing more than to destroy everything. At the Guardian Beasts' altar, the spirits of the Zyurangers finally appear. They appeal to their Guardian Beasts of the danger of Dai Satan's essence. Then they hear Daizyujin's voice, saying of course they will help.
Godzilla begins destroying buildings and leveling houses. The army is sent to attack him, but they are no match. Soon, after the Cosmos, Miki and Meru re-appear with Kenichi at the site, they feel the Earth beneath them rumble, as the Guardian Beast Tyrannosaurus rises to fight Godzilla. At first both fighters appear to be equally matched, until Godzilla's atomic heat beam pushes Tyrannosaurus back. Suddenly, ZyuMammoth appears and uses its Moth Blizzard (Mosu Burizado) to freeze Godzilla. But the mutanted dinosaur breaks free as Triceratops and SaberTiger use their Tricera Cannon (Torikera Kanon) and Saber Gun (Saberu Gan) respectively. Then from the air, Pteranodon fires its Ptera Beam (Putera Bimu). All this gives Tyrannosaurus time to do his jump kick on Godzilla, and finally using Tyranno Sonic (Tirano Sonikku).
Godzilla manages to get up and fire his heat beam again. The Guardian Beasts decide its time to combine - first forming the Beast Tank DinoTanker (Jusensha Dainotanka), using Beast Tank Cannon (Jusensha Kyanon) and Beast Tank Storm (Jusensha Sutomu), knocking Godzilla down again - and finally transforming into Daizyujin. Daizyujin then picks up Godzilla and throws him to the ground, as though to punish him. As he gets up again, Godzilla uses his heat beam, but Daizyujin uses his Mammoth Shield to protect him from the beam. Daizyujin then summons his weapon, the Dinosaur Sword Godhorn (Kyoryu-ken Goddohon), and uses his attack, Super Legendary Lightning Cut (Cho Densetsu Raiko Giri) on Godzilla. This unfortunately does not phase Godzilla and replies with another heat beam, knocking the giant god down.
Suddenly Godzilla is hit by a tail that's not his - it's Dragon Caesar! Caesar and Godzilla duke it out, giving Daizyujin time to recover. When Caesar's Dragon Hurley (Doragon Hare) fails to scratch Godzilla, the Guardian Beasts decide to go for another combo - Gouryujin. Armed with the Dragon Antler (Doragon Antora), Gouryujin manages to damage Godzilla a little, but not too much. Gouryujin then tries to use its Super Blaster Dragon God Thrust (Cho Bakuretsu Ryujin Tsuki) attack, but Godzilla manages to avoid getting stabbed and getting a heat beam in, causing Gouryujin to disassemble into its four components.
Not willing to give up for the sake of the Earth and the humans, the Guardian Beasts combine into Zyutei Daizyujin (Jutei Daijujin). Godzilla manages to survive Zyutei Daizyujin's Kaiser Burst (Kaiza Basuto), but his heat beam appears to bounce off the giant, who is armed with both the Godhorn and the Dragon Antler. After giving Godzilla two strikes from the weapons, Zyutei Daizyujin uses his Empire Attack (Enpaia Atakku). But when the smoke clears, Godzilla remains unscratched. He whips his tail against Zyutei Daizyujin's feet, causing the giant to fall into an abandoned building. Then Godzilla proceeds to use his heat beam.
Everyone who is watching the battle seem to think all hope is lost. Miki tries to communicate with Godzilla Junior and senses there are two sides, one which is his own, and the other being Dai Satan. Godzilla's will is trying to reject Dai Satan's will but he is losing greatly. Godzilla begs Miki to have him be destroyed (it would be the only way to stop Dai Satan), but Dai Satan's will not have it. Miki falls to her knees at the thought of losing her friend again, but Meru reminds her that it's what Junior's father would want. And eventually Miki agrees that Junior shouldn't suffer anymore and prays for a miracle.
Godzilla is suddenly attacked from behind - King Brachion has arrived at last and is using his fireballs to distract Godzilla long enough for Zyutei Daizyujin to get back on his feet. It is time for the final battle as Zyutei Daizyujin and King Brachion combine into their ultimate, true form - Ultimate Daizyujin. Godzilla seems unphased by this as he fires his heat beam. But to his surprise its having no effect on him. Ultimate Daizyujin tells Dai Satan (who is still inside Godzilla) to surrender and he would be spared, but Satan refuses. So now the army is left with no alternative as they help out one last time. As Godzilla is being fired by a barrage of cannons and missiles from the army, he tries one more time with his heat beam, but it is countered by Ultimate Daizyujin using his ultimate attack, the Gran Punisher (Guran Panissha).
The attacks appear to be equally matched, but Godzilla's heat beam finally gives up as Ultimate Daizyujins is finally defeating him. While Dai Satan's essense is disintregrating, a side Godzilla is saying to Miki, "Thank you", as Godzilla Junior finally colapses and explodes. His spirit then rises up and joins his father in the afterlife.
Every citizen who has seen the battle are both happy and sad at the same time. They first viewed him as a threat to the world, but now view Godzilla and Junior as friends. Now they thank the Cosmos and the 7 Guardian Beasts for their help. The Cosmos decide to live with Ultimate Daizyujin and the spirits of Zyurangers, but they promise to the world that if it is ever in trouble again, they will be there to help.
- Song of Daizyujin (Daijujin no Uta)