Soo Rin, a 6th grade student, moved due to her stepfather’s job. In her new school, people label her as a weirdo and avoid her after reading her blog. However, Sung Min, from the next class, befriends her and they fall in love. One day, Soo Rin, Sung Min, and Sung Min’s friends Tae Shik and Jae Wook go to the mountains. There they find a cave under a tree which leadsthem to a mysterious egg. Soo Rin then notices that the boys have disappeared and the police start looking for them. A few days later, Sung Min appears again but as an adult.