In the mountains of Gangwando, there is a prestigious private high school named Soo-Sin. The school is located in an isolated area and all the students and staff stay in dormitories. The students at Soo-Sin comprise of the top 0.1% of all the students in South Korea.
In order to get into Soo-Sin, students must prepare from elementary school. It is even harder to get into than Seoul National University. Because of this, students at Soo-Sin must compete fiercely and study even on weekends. Their only vacation days are the 8 days from Christmas Eve to the first day of the new year. During this time, the students and faculty leave the school. The school becomes empty.
On December 24, 2010, a bus full of students leaves the school. Diligent honor student Park Moo-Yul (Baek Sung-Hyun) stays behind because of a letter a received a couple of days ago. The letter is full of hate and states they will die, but leave a curse on Park Moo-Yul. At the school, only 7 students stay behind
