Jo Woo-mi

Every last Thursday of the month at an all-girls high school, the students of Class 2–5 cast their votes in a popularity poll. The results classify them into Grades A, B, C, D, and F. If they fall into Grade F, they become legitimate victims of school violence.

Kim Tae Ju is the eldest of three siblings. She is warm-hearted and tolerant, but she also has a hot temper. She cuts off relationships with people whom she doesn’t like. One day, Kim Tae Ju meets Lee Sang Jun again after many years. They attended the same elementary school. Lee Sang Jun is a popular actor. He is sensitive, imaginative, and smart. He is also the eldest sibling in his family. Since he was a child, he has been loved by his family deeply. His family was once in debt, but after Lee Sang Jun became successful, he paid off their debt and continues to support them financially. During filming for an acting project, Lee Sang Jun gets injured and goes to the hospital. There he meets his first love, Kim Tae Ju, whom he knew when he was an elementary school student.