Jin, a strange young man with a halo etched into his palm and exceptional combat abilities, lives in a beggar's colony with his grandpa. In another location, Amagi, an elderly scientist, is looking for professor Kanzaki to inquire about the whereabouts of the "player" Zet, a type of genetically enhanced human that they produced a few years ago. Jin and his grandfather are soon ambushed by an unknown guy who transforms into a monster. Professor Amagi's and Professor Kanzaki's relationship appears to link young Jin to the mystery of the "players" and Zet.