The students of the Barsburg Empire's Military Academy are trained to become capable fighters who will serve as the empire's newest soldiers. Every year, five hundred students take a graduation exam, where only 20 can pass to become honorable "begleiters," a position equivalent to assistant executive officers. Students fight their enemies by using "zaiphon," God-given abilities that take different forms depending on the individual. Teito Klein, the academy chairman's favorite student, is belittled by his peers due to his previous status as a slave. Despite being unable to fully remember his past, Teito's cheerful best friend, Mikage Celestine, stays by his side. After the two undergo the exam, Teito recalls small pieces of a long-forgotten memory, causing him to instinctively attack the c