The Black Bird Academy is a place that has no equal. Exorcists are trained in this dark school, whose task is to protect humanity from demons. When Lief Young wakes up in the Academy's dungeon, she can't believe what a handsome guy named Falco explains to her: a demon possessed her shortly after plunging a dagger into her heart! Falco is enchanted by Lief... Never before has a man been able to maintain control over his own body after being attacked by a demon without losing his mind. And then the Academy makes her an offer - if she studies to be an exorcist, her freedom will be returned. Falco is supposed to train her, but he doesn't know that Lief hears a voice in his head. And this is not human...