Asta and Yuno spend six months training for the upcoming Magic Knights Entrance Exam. Everyone seems to think Yuno is sure to pass, but worries that Asta is just wasting his time.

Suddenly the dungeon is host to several teams racing through traps to the treasure waiting in its depth—including a noted mage from an enemy nation.

Though the Magic Knights were able to save Marie from the Devil Banishers, Nero is taken once again and Asta’s 5-leaf clover grimoire is also stolen. Suddenly, they receive a message from one of Damnatio’s subordinates and learn the true identities of the Devil Banishers and Julius orders the Black Bulls yet again to save Nero. The Black Bulls begin their investigation in the town where they think the Devil Banishers were gathering. Will they be able to find out what the enemy’s true motive?