Oscar Saionji, a student at Zeltor Hero Academy, keeps his extraordinary abilities completely hidden, preferring to play the part of an ordinary, unnoticeable guy.
His reason? Simply because he thinks it is cool.

However, the quirky people around him—his beautiful classmate Serena, his Student Council President Aria, and his cool-headed swordsmanship teacher Raven—gradually begin to notice his hidden power.

With rivals, the student council, and even the Demon King standing in his way, what true power lies hidden behind the chuunibyou antics Oscar displays during classes and exams?