"Kinnikuman: Kinnikusei Ōi Sōdatsu-hen" is a continuation of the "Kinnikuman" franchise, focusing on the protagonist Suguru Kinniku, also known as Kinnikuman, a clumsy yet determined Chojin (superhuman) wrestler. The series centers on a high-stakes tournament to determine the rightful ruler of Kinnikusei (Planet Kinniku), the homeworld of the Kinniku Clan. The throne has been usurped by Kinnikuman’s evil twin brother, Ataru Kinniku, who frames Kinnikuman for crimes he did not commit, forcing him into exile on Earth.

The narrative begins with Kinnikuman returning to Kinnikusei to reclaim his birthright. To do so, he must participate in the "Chojin Crown Prince Survival Match," a brutal tournament where participants fight to prove their worthiness to rule. The tournament is structured as a series of intense wrestling matches, each with unique rules and challenges, pitting Kinnikuman against a diverse array of powerful Chojin warriors. These opponents include both allies and enemies from previous arcs, as well as new characters introduced specifically for this storyline.

Throughout the tournament, Kinnikuman is supported by his loyal friends and allies, such as Meat, his devoted manager, and Terryman, his best friend and fellow wrestler. The series delves into themes of perseverance, friendship, and redemption as Kinnikuman faces not only physical battles but also emotional and moral challenges. His growth as a leader and a warrior is central to the plot, as he learns to overcome his insecurities and embrace his destiny.

The stakes escalate as Ataru’s true motives are revealed, involving a deeper conspiracy that threatens the entire Kinniku Clan and the balance of power in the Chojin world. The series builds toward a climactic confrontation between Kinnikuman and Ataru, with the fate of Kinnikusei hanging in the balance. The narrative combines intense wrestling action with moments of humor, camaraderie, and dramatic tension, staying true to the spirit of the original "Kinnikuman" series while expanding its lore and character dynamics.