Yamada Seina's life is already teetering on the edge--between juggling high school, managing her friendships, and covering her rent solo, she barely has time to breathe. But when she nearly falls prey to a scammer and loses her hard-earned rent money, things go from bad to worse. Just when it seems like she's hit rock bottom, a mysterious (and incredibly handsome) stranger with horns swoops in, claiming he's a demon king who's crossed dimensions just to be with her. Why? Because, according to him, Seina is the reincarnation of his lost love!