Get on Board to stay alive! A divorced man, Seok-woo is always caught up at work, leaving him no time to spare with his daughter Su-an. Su-an decides take the KTX train to Busan by herself to see her mom and Seok-woo is pushed to accompany her to Busan. As the train departs, an abnormal virus spreads from a girl who is infected and people start to transform to zombies. Will Seok-woo and Su-an makr it out alive?