11-year-old Dong-ku, who is retarded, is the school's water boy until, that is, the school installed a water purifier system. Disappointed, Dong-ku soon learns the school's baseball team needs a water boy and so he decides to join the team.

While a zombie virus breaks out in South Korea, passengers struggle to survive on the train from Seoul to Busan.

The story of Pil-Joo, an Alzheimer's patient in his 80s, who lost all his family during the Japanese colonial era, and devotes his lifelong revenge before his memories disappear, and a young man in his 20s who helps him.

Nora and Hae Sung, two deeply connected childhood friends, are wrest apart after Nora's family emigrates from South Korea. 20 years later, they are reunited for one fateful week as they confront notions of love and destiny.