Every Thursday afternoon, once a month, students at Sarang High School cast their votes in a popularity poll. The result? A brutal ranking system that determines the entire social hierarchy of the school. After starting at the bottom, can new transfer student Su Ji make her way to the top of the pyramid? Or will she topple the game altogether?
E1
New student Seong Su-ji is introduced to a ranking system called the Pyramid Game that chooses class outcasts via secret vote. Su-ji must decide whether to accept her status, or partner with a fellow outcast to topple the Pyramid Game.
E2
Su-ji becomes the target of vicious bullying when she discovers a popular classmate is related to the inventor of the Pyramid Game. A teacher offers to help Su-ji, while a blackmail scheme is revealed. Su-ji shares a resolution with Ja-eun.
E3
After the latest Pyramid Game vote, Su-ji and Ja-eun improve their class rankings. Ja-eun tries to protect the newest outcast, while Su-ji feels it's not her business to intervene. Su-ji finds out she had help behind the scenes.
E4
Su-ji and Ja-eun continue to search for allies in their quest to eliminate the Pyramid Game. Unable to convince their classmates, they look for options outside of the school, like hacker Cho Seung-hwa. A bullied girl searches for a way out.
E5
Su-ji finds trouble when a classmate reaches a breaking point on parent visitation day. Ha-rin sends a warning when Su-ji loses Ha-rin's vote. Su-ji's plans gradually fall apart thanks to a friend's betrayal. The 15th game brings an unexpected twist.
E6
A shocking reveal after the 15th game disrupts the class rankings, and prompts complaints from students about flaws in the voting app. Ha-rin has a plan to restore order. A savage game of dodgeball works to Ha-rin's advantage...until the ball stops.
E7
Su-ji is trapped by Ha-rin's blackmail. She feels bad keeping a secret from Ja-eun. The class goes on a school trip. Tension builds until everything explodes in a game of survival.
E8
The students are upset about a violent assault that occurred during the class trip. A powerful allyship gives Su-ji hope. Su-ji acts on her plan to take down Ha-rin.
E9
The big day has arrived. Issues develop between Su-ji and her friends. A winning move is made against Ha-rin. The public learns about the Pyramid Game. Ha-rin finally contacts Ja-eun.
E10
Su-ji and her classmates make a final attempt to return to normal life and a safer environment. Ha-rin and Ja-eun's history is revealed.