Kim, vice president of the Mystery Research club, works late on the club's magazine. Crossing a bridge, he encounters a seemingly kind grandma who triggers memories of a ghost story. The story involves a wartime orphanage, a mysterious disappearance, and a warning not to answer the grandma's question. The encounter takes a chilling turn as the grandma transforms into a demon. Kim wakes up, questioning the boundary between dreams and reality, haunted by the ominous warning.