Martial law is imposed on the city. When Cheong-san is separated from the rest of the group, On-jo leads a mission to use a drone to locate him.

Inside Lee Byeong-chan’s science lab, a student incurs a seemingly harmless bite. Shortly after, a fast-spreading outbreak soaks the school in blood.

The infected multiply in droves. Scrambling for their lives, Nam On-jo and Lee Cheong-san find safety with others inside a classroom — but not for long.

When one of the group is scratched while fighting a zombie, Lee Na-yeon demands they kick him out. Outside, the virus swallows up the city.

In need of a cellphone, two students take a risky journey to the teachers’ office. Byeong-chan passes on critical information to Detective Song Jae-ik.

The infected multiply in droves. Scrambling for their lives, Nam On-jo and Lee Cheong-san find safety with others inside a classroom — but not for long.

When one of the group is scratched while fighting a zombie, Lee Na-yeon demands they kick him out. Outside, the virus swallows up the city.

In need of a cellphone, two students take a risky journey to the teachers’ office. Byeong-chan passes on critical information to Detective Song Jae-ik.

Martial law is imposed on the city. When Cheong-san is separated from the rest of the group, On-jo leads a mission to use a drone to locate him.

Inside Lee Byeong-chan’s science lab, a student incurs a seemingly harmless bite. Shortly after, a fast-spreading outbreak soaks the school in blood.

As a state of emergency is declared, the residents tie up Pyeon Sang-wook for being bitten. Hyun-su is unable to ignore a family in distress.

Hyun-su saves the others from a deadly attack. Running out of necessities, Eun-hyeok announces a plan to venture outside for resources.