Tokyo Butei High School--- A special school where armed detectives, also known as "Butei", are trained. Tohyama Kinji is a sophomore student who has a unique body that activates a "super mode" when it is stimulated by "something". He tries to hide it from others in order to live a peaceful life, but trouble comes to find him when he becomes the victim of a bombing incident, where he meets the Butei High "Assault" department elite, Aria H. Kanzaki.