This is the story of a teenage boy named Takeru Tachibana and his struggle to recover his sister Sayoko from a "cyborg dogfight circuit". When Takeru was 10 years old, his town was bombed during an enemy air-raid in which his parents were killed and he was mortally wounded. Sayoko, cut deep with "survivor's guilt" and a "co-dependent" inability to deal with living alone, rashly sells her brain to the Albion Corporation run by a mysterious CEO named Véltare Marçeau in order to pay for a risky surgical operation that Takeru may or may not survive. Her brain is placed in a cybernetic body, the process of which essentially eliminates the brain's memories and heightens its aggression. Her new identity is The White 13, or "The Ice Doll", and for the next five years she is placed on a dogfight circuit fighting other cyborgs in gladiator-style extravaganzas where she eventually becomes the grand champion and obtains the rank of "sirius"...