Contains spoilers for this episode and earlier episodes.
Nam-ra tells Su-hyeok that his voice helped her resist the urge to bite him, and he admits his feelings before they kiss. Her altered condition also sharpens her hearing, letting her detect activity elsewhere in the school. Eun-ji attacks a teacher after eating live fish in the infirmary. Gwi-nam uses his own new abilities to find Myeong-hwan, then turns on the former leader who still expects him to obey and act as bait.
The students in the music room build a barricade from furniture and plan to draw the infected inside, clearing the corridor for a climb to the roof. Music and shouted insults attract more zombies than they can easily hold back. Su-hyeok stays behind to help open the way as the others move. The barrier eventually collapses, sending the horde after them. The separate archery group struggles to move its injured companion, while Jae-ik's escape is interrupted by another person needing rescue.
Outside Hyosan, the military studies an infected soldier, and Assemblywoman Park urges command to search the school. So-ju has reached the mainland and continues toward his daughter. A helicopter finally lands above the students, but Cheol-su keeps the roof door shut despite their calls. They are trapped on the stairs with zombies coming up behind them. A tarpaulin buys a little time against the crowd, until Gwi-nam reaches the stairwell and faces Cheong-san again.