Long ago, the Grongi Tribe terrorized the Linto Tribe until a warrior acquired the power of Kuuga and defeated the Grongi, sealing their leader within a cave. In the present day, Kuuga's mysterious stone belt is excavated, freeing the Grongi as they resume their murderous game on the Linto Tribe's descendants: humanity itself. But a multi-talented man named Yusuke Godai finds himself drawn to the belt and becomes the new Kuuga. He helped assemble the Science Police to fight the Grongi to ensure the happiness and safety of others. But as the endgame draws near, Yusuke learns of a horrible revelation between Kuuga and the Grongi Tribe's leader.