Kaiko City is plagued with poverty and crime. When a corrupt businessman decides to run for mayor and starts eliminating opponents from the rival mafia, a former police captain serving time for murder is secretly released and put in charge of a special task force to arrest him.

Four girls take part in illegal underground fighting event "Girl's Blood" held at an abandoned school building in Roppongi every night. The girls have their own stories and quirks from their private lives. Satsuki (Yuria Haga) suffers from a gender identity disorder, Chinatsu (Asami Tada) ran away from an abusive husband, Miko (Ayame Misaki) is a S&M queen and Mayu (Rina Koike) has a Lolita face.