A giant robot made from dinosaur parts pulls itself from the ocean and becomes Earth's only answer to an alien supercomputer that's been waiting thousands of years for this moment. The crew piloting it is ridiculous, a sumo wrestler, an American pilot, people who have no business flying a weapon this big, and that mismatch is exactly where the show finds its soul. You're watching 1976 decide that the last hope for humanity doesn't need to be tragic or serious; it just needs to work, one impossible fight at a time.
When a massive alien fleet arrives to conquer Earth, humanity's only defense lies with an unlikely crew aboard the flying aircraft carrier Daiku Maryu. These misfits, a sumo wrestler and kickboxer among them, pilot giant robots to fight off the invading forces of Zela, a dying planet whose supercomputer ruler Emperor Darius will stop at nothing to claim our world as salvation for his own people. Enter Sanshiro Tsuwabuki, a hothead baseball player whose arm was crippled in a Zelan assault. Burning for revenge, he becomes the pilot of Gaiking, the team's most powerful mecha weapon. Raw, aggressive, and determined to prove himself, Sanshiro joins this ragtag band of warriors in a desperate battle that will test their courage and unity against an enemy that once guided humanity's ancient civilizations. As battles rage across the planet, the crew must uncover why Zela truly wants Earth and whether there's any hope of stopping an invasion backed by cosmic forces beyond their comprehension.