After failing the entrance exams to her school of choice, Hiyo Osora gets an acceptance letter from SM Academy. But she didn't even apply or take its exam! When she arrives, there's something amiss -- all the students are... monsters!? And the head of the student council says he's her fianc right before he sprouts giant black wings! What strange fate brought Osora to SM Academy, and what supernatural fate awaits her after this!?