In a world where demons exist alongside humans, the main character is a boy whose father works for demonkind. Despite being human, the boy is chosen by a special card believed to be called the Lovers card, which grants him the right to participate in a succession battle to become the next Demon King. He enrolls in a prestigious school attended by demon card holders, where the current Demon King serves as principal. The students fight one another, and the victor will ultimately claim the throne. Along the way, the protagonist befriends several demons who choose to join him in his quest throughout the succession battle.