Everyone thought it is something fun, but to Chorong, the trip was something she never agree. Without Luhan, her boyfriend, persuading her, she would never had participated in the trip. Everything goes as planned. The Group of friends arrived at the Red Cave earlier than the time they should. Just as planned, Jongdae, the person in charge of the trip went for his explanation about the cave once everyone assembled outside the caravan. Soon after that, the group went into the cave and spent a night there. Everyone has their enjoyment inside the dark, chilly place. Their luaghters fill the air at any moment...until everything changes...