Hyo-joo, an untenured instructor at a boys’ high school is assigned to a class of seniors as a HR teacher. She notices that a specialized dance student Jae-ha is absent from the self-study session, and finds him practicing refined dance movements in the gym. The next day Hae-young, the school board chairman’s daughter arrives as a tenured instructor, which was the position assumed to be offered to Hyo-joo soon. Hae-young, sweet and having grown up with no worries, treats Hyo-joo with affection, but Hyo-joo only gives her the cold shoulder. Then one day, Hyo-joo witnesses Hae-young and Jae-ha in the gym, having sex, and from that moment on, she starts feeling an inexplicable sense of humiliation towards Hae-young while gradually falling under the influence of Jae-ha’s elusive charm.

Min-Ah finds a strange diary, capable of arousing hallucinations, kept by two of her senior fellow-students, Hyo-Shin and Shi-Eun, who seem to have an unusually close bond. But Hyo-Shin suddenly kills herself, for no obvious reason, and the entire school is shocked and depressed. Min-Ah, however, starts to feel different. It's almost as if she's somehow possessed by the dead girl... Written by Anonymous