Contains spoilers for this episode and earlier episodes.
Cheong-san cannot bring himself to abandon his infected mother, even as his friends defend themselves against her. The group pulls him away and runs through the rain. Hyo-ryeong falls and Ji-min leaves her behind, while Wu-jin turns back to help. The encounter brings the younger students together with Ha-ri's group and reunites her with her brother. Their escape into the gymnasium goes wrong when the infected inside overwhelm them, and Jun-seong is killed before the others find shelter.
The survivors hide in a storage room and argue about what to do next. They share a little food, introduce themselves properly and eventually vote on a plan to move across the gym. Equipment carts can form a rolling barrier around them, although someone must keep pushing while zombies press against it. Outside the school, the military's examination of Byeong-chan's research brings no workable vaccine. Reports that the infected have broken containment lead the commander toward bombing targets in Hyosan.
The students pad their bodies and push the carts out into the gym. The barrier is soon surrounded, and Joon-yeong is bitten during the struggle. He leaves its protection and pushes from outside, drawing attackers onto himself so the others can keep moving. His sacrifice carries them as far as the exit, where a chain and padlock stop their progress. So-ju arrives on the other side and opens the doors, finally reaching On-jo after his journey through the city.