To conquer the dungeons that suddenly appeared on Earth a hundred years ago, students now attend academies to train as adventurers. Among them are two rivals: the academy’s strongest delinquent, Sainokami Kuroto, and the elite noble honor student, Mononobe Yukihime. One day, the two of them find themselves trapped in a dungeon… inside a room that they can’t escape unless they hold hands!? Will these sworn rivals be able to clear this high-difficulty mission and conquer the dungeon—!?