Train to Busan

A deer is hit by a truck and turns into a zombie deer after the truck leaves. Seok-woo, a cynical workaholic and divorced father in Seoul, messes up a birthday present for his estranged daughter Su-an, and misses out on her recital of the Hawaiian folk song "Aloha ʻOe". He agrees with Su-an to take her to see her mother Na-young in Busan.

The next day, they board the KTX 101 for Busan at Seoul Station, along with blue-collar worker Sang-hwa and his pregnant wife Seong-kyeong, high-ranking executive Yon-suk, a high school baseball team including player Yong-guk and his cheerleader girlfriend Jin-hee, elderly sisters In-gil and Jong-gil, and a traumatized homeless man. Just before departure, a scraped up woman boards the train unnoticed at the last minute. News reports reveal that an outbreak is occurring across the country, and the scraped up lady then turns into a zombie. She bites and infects a train attendant, sparking a rapid outbreak on the train.

The survivors flee to other carriages on both sides of the train and secure the doors, trapping the horde in the process. The train passes through Cheonan station, and continues onto Daejeon Station, where a group of soldiers were deployed to keep the infection at bay. Seok-woo is notified that his company sent an extraction team to pick him up and Su-an. After stopping at Daejeon, the passengers disembark from the train, but find that the deployed soldiers and those from Seok-woo's company, had also fallen to the horde. The passengers flee back to the train, becoming separated into different carriages in the commotion.

The conductor cancels all future stops except for Busan, where the army has established a quarantine zone. Seok-woo, Sang-hwa, and Yong-guk arm up, sneak and fight through the zombie horde to reunite with Su-an, Seong-kyeong, In-gil, and the homeless man in another carriage. The remaining passengers, fearing that the survivors are infected, refuse to let them into their carriage and block the door. Seok-woo and the others start to try and get into the safe carriage, however Sang-hwa is bitten during the process and tells Seok-woo to look after Seong-kyeong, name their daughter Yoon Su-yun, and sacrifices himself to buy the others time to force open the door, but In-gil is left behind in the process.

Yon-suk, train attendant Ki-chul, and the other passengers demand that the new passengers leave their train compartment and isolate themselves in the front vestibule. Jong-gil, disgusted at everyone else's selfishness and paranoia that led to her sister's death, opens the door to let the zombies in and kill everyone else left onboard but the survivors in the locked up vestibule. Seok-woo learns from a phone call that his company was indirectly responsible for the outbreak. Yon-suk and Ki-chul escape by hiding in a bathroom. A blocked track at Dongdaegu Station forces the train to stop, and the driver disembarking to search for another train. Yon-suk escapes after pushing Ki-chul into the zombies.

A flaming locomotive barrels in and crashes into some of the zombie-filled passenger carriages, trapping Seok-woo, Su-an, Seong-kyeong, and the homeless man beneath a toppled carriage. Yong-guk and Jin-hee get split up from the party and are used as bait by Yon-suk, as he escapes for the new train. The conductor starts up another train on a separate track and tries to help an injured Yon-suk, but is mauled in the process. Seok-woo, Su-an, and Seong-kyeong find their way out from under the carriage after the homeless man sacrifices himself.

Seok-woo, Su-an, and Seong-kyeong board the new train, only to find an infected Yon-suk, who desperately begs them for help before turning into a zombie. Seok-woo fights him off, but his hand is bitten during the tussle. In his last moments of consciousness, he puts Su-an and Seong-kyeong inside the engine room, tells Seong-kyeong how to drive the train, and says goodbye to Su-an. Seok-woo, before succumbing to the infection, runs to the back of the train and reminisces about Su-an's birth before throwing himself off the train.

The surviving pair arrive at a blockade of corpses and barbed wire outside a tunnel near Busan, both walk through the tunnel, with Su-an singing "Aloha 'Oe" to calm her nerves and pay tribute to her father. Su-an and Seong-kyeong are met by the army, who brings both of them to safety.