Min-Ah (Kim Gyu-Ri) spots a maroon diary near a water fountain at school. She’s late for class and takes the diary with her. In class, Min-Ah opens the diary and experiences a brief hallucinatory experience. The diary originally belonged to two girls that attend the same school, Hyo-Shin (Park Ye-Jin) and Si-Eun (Rie Young-Zin). The two girls seem to share a relationship that’s closer than even best friends.