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.

Based on the popular manga, Oh Ha Ni is a clumsy student who falls the perfectionist, Baek Seung Jo. However Seung Jo is indifferent towards her and rejects her love. When Ha Ni's house collapses, she and her father move into his long-time friend's house. It turns out that Seung Jo is the friend's son and Ha Ni is given the opportunity to be near the guy she loves. Will she be able to move Seung Jo's heart?..

Jan Di is an average girl whose family owns a dry-cleaning shop that is located near the luxurious and well-known Shin Hwa College. Jan Di meets the four most richest and spoiled boys when she delivers laundry to the school one day. The boys are known as the F4 and cause trouble to those who speak out against them.