Pyramid Game - Season 1 Episode 3 The Birth of a Trio The hierarchy war.
Overview: 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.