"King of Prism: PRIDE the HERO" is a sequel to the "King of Prism" film series, continuing the story of the Over The Rainbow idol group and their rivals. The narrative centers around the Prism King Cup, a prestigious competition where male idols perform dazzling Prism Shows, combining figure skating, dance, and acrobatics. The stakes are high as the winner earns the title of Prism King and gains immense recognition in the idol world.

The story begins with the Over The Rainbow members—Hiro, Shin, and Aoi—facing new challenges as they prepare for the Prism King Cup. Their rivals, including the Schwarz Rose group and the Edel Rose duo, are determined to claim victory, creating intense competition. Hiro, the protagonist, struggles with self-doubt and the pressure to live up to his reputation as a top idol. Meanwhile, Shin and Aoi face their own personal and professional hurdles, testing their resolve and teamwork.

New characters are introduced, such as Kakeru Juuouin, a talented but enigmatic idol with a mysterious past, and Yukinojou Tachibana, a former Prism King who returns to the stage. These additions bring fresh dynamics to the competition, as alliances shift and rivalries deepen. The narrative explores themes of ambition, perseverance, and the bonds of friendship, as the characters strive to achieve their dreams while overcoming internal and external obstacles.

The Prism King Cup serves as the central event, with each performance showcasing the characters' growth and determination. The competition is not just about winning but also about self-expression and pushing the boundaries of what Prism Shows can achieve. The story culminates in a climactic showdown, where the characters' hard work and passion are put to the ultimate test, leaving a lasting impact on their careers and relationships.