Renton Thurston desires to leave his home behind and join the mercenary group known as Gekkostate, hoping to find some adventure. When a robot crashes through Renton's garage the meeting sparks the beginning of Renton's involvement with Gekkostate as he takes off alongside the young girl Eureka as the co-pilot of the Nirvash.
On the island of Iwado, 13 year-old Ao Fukai lives with an aging doctor after the disappearance of his parents. When Iwado is attacked by an organization known as Secret, Ao unexpectedly finds himself at the controls of the Nirvash, a robotic fighting machine. Alongside his childhood friend Naru Arata, a teen girl with psychic powers, Ao heads into battle, determined to protect his island home.