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.
The series follows the bittersweet relationship between a banchan shop owner whose daughter enters the war of Korea's college entrance exams, and a top hagwon instructor.