A seemingly ordinary young student named Koichi begins experiencing strange, recurring dreams of a solitary tower rising from a vast desert. These visions soon lead him on a journey to Baghdad, where he discovers that the tower from his dreams is real, an ancient structure known as the Tower of Babel that lies dormant in the desert sands. Upon reaching the tower, Koichi learns a life-altering truth: he is not an ordinary human. He is the direct descendant and rightful heir of Babel, a powerful extraterrestrial being who crash-landed on Earth 5,000 years ago. As the successor, Koichi inherits the title of Babel II, along with tremendous psychic abilities and the immense responsibility of defending the planet.

The legacy of Babel comes with three powerful, loyal guardians. The first is Rodem, a cunning and shape-shifting black panther. The second is Robross, a giant, pterodactyl-like flying creature that serves as a swift mode of transportation. The third is Poseidon, a colossal robotic warrior that rises from the depths of the ocean when summoned to battle. Together, this unlikely team must protect the world from emerging dark forces. The primary threat is an evil cult leader or psychic revolutionary known as Lord Yomi, who seeks to gather other super-powered individuals under his command to dominate the world. Yomi is himself another descendant of the original Babel, making him a formidable and personal nemesis to Koichi. The young hero must learn to tame his latent psychic power and master his new role to stop Yomi's plans.

The conflict is global, taking Koichi from his life in Japan to confront Yomi's schemes in various international locations, including the deserts of southern Asia, the streets of Manhattan, a hidden base in the Swiss Alps, and the mystic confines of the Tower of Babel itself. In his battle against Yomi, Koichi is not alone; he is often aided by a group of authorities or allies, such as a medical examiner named Saeki who helps investigate the strange phenomena caused by the antagonists. His journey forces him to grapple with the immense weight of his heritage. In some versions of the story, Koichi resists fully abandoning his human identity and emotions to become a perfect instrument of power, a struggle that his enemy Yomi does not share. The final confrontation tests his courage and will, as the fate of humanity rests on his ability to embrace his destiny as Babel II, the defender of the Earth.