Kinji Tooyama gets by as an unremarkable E-rank student at Tokyo Butei High, a school that trains armed detectives, hiding a power called Hysteria Mode that only surfaces when he's under enough pressure. On his way to class he finds a bomb rigged to his bicycle, and the S-rank student who pulls him clear, Aria H. Kanzaki, a descendant of Sherlock Holmes, sees the power surface firsthand and decides on the spot that he's going to be her partner. This manga adapts Chuugaku Akamatsu's light novel series.