Tokyo is a dark technopolis, a city of faceless chrome and cold marble. It is ruled by Nogi, a yakuza boss specializing in drugs and murder. He gained absolute power by executing the former boss and marrying his daughter, Chiaki. Only the mysterious Ikko, Chiaki's half sister, threatens him. Inspired by a legendary hit woman, Ikko calls herself the Black Angel and plans to wash away her father's murderer with a deluge of blood. Ikko's vengeance burns out of control as a web of intrigue, double-crossing and mistaken identity comes crashing down around her.