The deaths of Jin-ha and Kyung-jun, both innocent Citizens, heighten the students' sense of entrapment. The prevailing unease about the unreliability of seemingly plausible information forces them to prioritize unmasking the Mafia swiftly for their own survival. Meanwhile, So-mi, for some reason, begins to cast doubt on Na-hee, setting the stage for a sudden turn of events.

With Na-hee exposing her identity, everyone discovers that So-mi's the Mafia, placing Na-hee in danger with her police role now known. Holding herself responsible for her friends' deaths, Na-hee devises a plan to unveil the Mafia even after her potential death. Although clues surface, they are too ambiguous to conclusively identify the Mafia. Meanwhile, the focus shifts to Mi-na as the next target in the voting process.

Everyone corners Yeon-woo as the Mafia because he got wounded. He tries to defend himself, but he gets voted in the end. Da-bum feels relieved, and Jun-hee catches that moment. He confronts Da-bum and tells him not to kill Yoon Seo and Jung-won. Yeon-woo's identity is revealed, and Yoon-seo finds out who the last Mafia is. Meanwhile, Da-bum wants to end the game to avoid being suspected.