At Tokyo Butei High School, a prestigious institution training armed detectives known as 'Butei,' Tohyama Kinji, a sophomore with a special ability that triggers a 'super mode' under specific conditions, strives to keep this power concealed for a tranquil existence. However, his efforts are thwarted when he becomes entangled in a bombing episode, leading to an encounter with Aria H. Kanzaki, a formidable member of the elite 'Assault' division at Butei High.