Hidan no Aria緋弾のアリア; Aria the Scarlet Ammo; 비탄의 아리아; 绯弹的亚莉亚; Aria la Balle écarlate; Ария по прозвищу Алая Пуля; Phi đạn Aria

Tokyo Butei High school--- It was a special school where armed detectives, also known as “Butei“ are being brought up. Tohyama Kinji is a sophomore student who has the unique body which activates a “super mode“ when it was stimulated by “something“. He tries to hide it to others in order to live a peaceful life. But trouble came to find him when he became a victim of a bombing incident, where he met the Butei high “Assault“ department elite, Aria H. Kanzaki.