A young boy named Yuta Hibiki awakens in the home of his classmate Rikka Takarada, with no memory of his past and sees hallucinations of a robot named Gridman in an old computer terminal in Takarada's family store. The next day, Yuta meets his friend Sho Utsumi, who helps him cope with his amnesia. Intrigued by Yuta's story about Gridman...