| Kim Yo Han is a psychiatrist who gets involved in a serial murder when his car broke down on Christmas Eve during a sudden storm and he is forced to take shelter at a private high school. Seven students and a teacher are also there over the winter break, but they are gradually murdered one by one as they receive letters from a killer who wants revenge for the death of his mother and sister. |
| Name | Character | Episodes |
|---|---|---|
| Kim Woo-bin | Kang Mi-reu | 8 |
| Esom | Yoon Eun-sung | 8 |
| Kim Young-kwang | Jo Young-jae | 8 |