Hikaru Shihodo is a 17-year-old student operating secretly as the armored superhero Hikaruon. His mission targets Uraer, an evil organization from another dimension. Dispatched to investigate a disturbing series of unexplained student suicides at his own school, he adopts the identity of a transfer student to infiltrate the student body and conduct his investigation.

Immersing himself in student life and collaborating with his 22-year-old homeroom teacher, Azumi Hazuki, he gathers intelligence. Though the school initially appears dominated by money and status issues, Hikaru deduces the suicides originate from supernatural manipulation, not typical adolescent struggles. He uncovers an interdimensional entity exploiting and controlling vulnerable students for its own purposes.

As Hikaruon, he employs advanced technology, including a specialized combat suit and a powerful super bike, to battle Uraer's forces. This transformation enables him to confront the Demonic Beasts and other entities unleashed by the organization. The conflict culminates in his efforts to stop the interdimensional mastermind orchestrating the tragedies and sacrificing innocent lives.

Hikaru's background prior to becoming Hikaruon remains unspecified. His development centers on his undercover investigation, the progression of his mission against Uraer, and his ultimate confrontation with the source of the evil influencing the school. Information regarding further appearances, expanded backstory, or development in other official media beyond the original OVA is unavailable.