Sung Soo Ji transfers to Baekyeon Girls' High School in Seoul and begins classes there in Grade 2, Class 5. On her first day at her new school, she notices that her class is generally peaceful, but also a little strange. He has to participate in a strange vote called the Pyramid Game, where 2nd and 5th grade students participate. The game is held once a month and is like a popularity vote, but the student who gets the fewest votes gets an "F" and becomes a target for school violence. Sung Soo Ji gets zero votes and becomes the next target, her classmates harass her and no one seems to care about that in her class. Sung Soo Ji tries to get out of his situation and also tries to put an end to the Pyramid Game at his school.