Hikaru Amaki is a clumsy and clumsy otaku girl. One day, while Hikaru is having a fun time with her friends at an amusement park, she is attacked by a mysterious cyborg named Garbage. Hikaru was a princess who descended from the royal family of Granners, located far away in the universe. Hikaru wears the royal armor (Grand Suit), the proof of being the heir to the throne of Planet Granners, and transforms into Grandeur. They have to face an assassin from outer space who is trying to steal the royal armor.