When a zombie virus pushes Korea into a state of emergency, those trapped on an express train to Busan must fight for their own survival.

All unemployed, Ki-taek's family takes peculiar interest in the wealthy and glamorous Parks for their livelihood until they get entangled in an unexpected incident.

Based on actual events that took place at Gwangju Inhwa School for the hearing-impaired, where young deaf students were the victims of repeated sexual assaults by faculty members over a period of five years in the early 2000s.