Simon, an exorcist, meets Orphe, a beautiful bard with "demonic" singing ability. Simon decides to accompany him to his mother's hometown to find out who he really is. But that night, he is attacked by a demon who calls Orphe "the key." They complement and support each other as they exorcise the demons that stand in their way with their swords and songs! An outlaw exorcist and a half-demon bard interweave in this exciting buddy story!