Black Bullet unfolds in a near-future world ravaged by the parasitic Gastrea virus, which has forced humanity to survive behind towering Monolith walls. In the Tokyo Area, order depends on Civil Security teams built around two partners: a Promoter, who plans missions and provides protection, and an Initiator, a young girl infected by Gastrea whose condition grants her formidable abilities at a terrible personal cost. Rentaro Satomi and Enju Aihara become one of those teams, taking on dangerous jobs in a city where fear of the infected runs almost as deep as fear of the monsters outside the walls.
As outbreaks continue to spread, their work draws them into conflicts over security, prejudice, and the hidden forces shaping life inside the city. Black Bullet balances fast-paced action with a bleak, uneasy atmosphere, using each mission to show how fragile civilization has become. At its heart, the series focuses on the bond between Rentaro and Enju and on the Cursed Children who stand between humanity and collapse, asking what it really means to protect people in a society built on desperation, distrust, and fragile hope.