Soo Ji transfers to Baekyeon Girls’ High School and discovers that her class plays a game called the Pyramid Game in which the students decide on a hierarchy based on a popular vote. As Soo Ji ends up in the lowest rank, she devises a plan to get back on her feet.

Soo Ji is determined to figure out the characteristics of her classmates and the mastermind behind the Pyramid Game. She also tries to join forces with other girls who seem vulnerable. She even asks her homeroom teacher for help, only to be disappointed. Meanwhile, the 14th Pyramid Game begins, and Ja Eun, who kept skipping school, shows up.

Soo Ji moves up to Grade C, and the treatment she gets changed completely overnight. She breaks the promise she made with Ja Eun, but she decides to join hands with her and help the new girl in Grade F, Pyo Ji Ae. Soo Ji, Ja Eun, and Ji Ae come up with a plan to destroy the pyramid altogether.

Soo Ji begins to feel uneasy about the unfolding events, suspecting that her plan may have been compromised and that Ha Rin is catching on. Learning this, Pyo Ji Ae worries she may have made a mistake and dreads the potential consequences. Meanwhile, Soo Ji hints to Hae Jun that she holds leverage over her, coercing Hae Jun into assisting her. Soo Ji recruits a hacker to join her team.

During the parents' visit to the school, Soo Ji gets caught up in Ha Rin's trap. While Soo Ji tries to make a pact with Do Ah, Seung Yi puts on a show to put Soo Ji on the spot. Although the parents witness the ordeal, Ha Rin turns the situation to her advantage and even has her grandmother, the chairwoman of Baekyeon Group. Meanwhile, Soo Ji switches to her Plan B.