Strange rumors begin to disperse later Unjoo committed suicide at the catholic girls' high school . Unjoo's younger sister Jung-un who attends the exact same school becomes leery about Unjoo's departure. After evaluation that is persistent, Jung-un finds out on the night of this incident, prior to building a toast on 40, Soy, Eugene, Eun-young the four of them had tried to perpetrate a joint suicide. However, the three remain living, and Unjoo had expired. The desire, jealousy, and lies supporting the pledge of departure between your four girls are revealed, along with the truth behind the suicide of Unjoo.