After failing the entrance exam for the high school she wanted, Hiyo Osora gets an acceptance letter from SM Academy, a school she never applied to, and discovers that its students are monsters wearing human faces. Student council president Kurou Tenma greets her by announcing that he is her fiance, then unfolds a pair of huge black wings. Hiyo turns out to come from the same line of crow monsters he does, which leaves her enrolled, engaged and surrounded by yokai she never knew existed.