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.

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.

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.

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.