Hidan no Aria is set in a Japan battered by rising crime, where Tokyo Butei High trains armed detectives known as Butei to act like mercenary agents of justice. Kinji Tooyama, a blunt and antisocial sophomore, has withdrawn from the combat-focused Assault Division and tries to live quietly in the logistics track while hiding a powerful special ability that is as useful as it is embarrassing. That fragile routine ends when he becomes the target of the notorious Butei Killer.
In the middle of that crisis is Aria Holmes Kanzaki, an outspoken, emotional prodigy of the highest rank who saves Kinji’s life and then decides he should become her partner. Forced together by danger, the two navigate brutal training exercises, criminal threats, and the uneasy balance between Kinji’s reluctant talent and Aria’s fearless drive. As they are pulled deeper into the world of Butei, their partnership becomes a constant test of trust, survival, and whether two people with very different temperaments can function as a team.
