A man (Gong Yoo), his estranged daughter and other passengers become trapped on a speeding train during a zombie outbreak in South Korea. As the train departs, a spasming young woman boards the train with a bite wound on her leg. The woman succumbs to the bite and becomes a zombie, attacking a female train attendant. The zombie infection spreads through the train, including the baseball team, but baseball player Yong-guk, his girlfriend Jin-hee, two of their friends, and several passengers manage to escape. News broadcasts report zombie outbreaks throughout Korea. The train stops at Daejeon, but the surviving passengers find the city has also been overrun, and they retreat back to the train, splitting up in the process. The conductor restarts the train to head to Busan, where a successful quarantine zone has reportedly been established.