A species of parasitic aliens descends on Earth and quickly infiltrates humanity by entering the brains of vulnerable targets; insatiable beings that gain total control of their host and are capable of transforming themselves to feed on unsuspecting prey. High school student Shinichi Izumi falls victim to one of these parasites, but the creature fails to take over his brain and ends up in his right hand.
Eijun Sawamura is a pitcher who joins an elite school with a brilliant catcher named Kazuya Miyuki. Together with the rest of the team, they strive for Japan's storied Koushien championships through hard work and determination.
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.
