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.

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.

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.