Takashi Katori is a big fan of online games, and so is his American friend Sarah. However, one of their RPGs goes too far, as their virtual world and the Lezarion robot that Takashi created for the game somehow mix with reality. Takashi is caught, but later the Earth Governement discovers that an evil scientist from the Moon is hacking into virtual worlds and security, so they force Takashi to pilot the Lezarion and protect the Earth…