Synopsis
Tsuwabaki Daiya, a boy, spotted a black fire in the ocean while he and his father were on a small boat. A huge monster emerged from that fire, and his father along with the crew vanished into the sea. Just as Daiya was about to meet the same fate, a massive mecha dragon appeared and rescued him. Five years later, Daiya is now a junior high school student. When a giant monster reappears, he encounters the mecha dragon known as "Daiku Maryu." The dragon's head separates from its body and transforms into the torso of a super robot called Gaiking. Daiya climbs into Gaiking, battles the monster, and defeats it. He discovers that there is an enemy scheming to conquer the world, so he sets off for another world named Darius to put a stop to their plan.
