Plot - A man and a woman meet on the KTX train and due to sudden breakdown of train they spend 24 hours in the city of Busan, South Korea.
Soo-jeong has been dating her boyfriend for 10 years, but their relationship is not going well. One night before to her business trip to Busan, she feels distract when she heard that her friend is getting married to her first love. On the journey she sit next to Jae-hyeon and he get attracted to her and do every possible thing to make her fall in love with him. Due to sudden breakdown of train they share the car ride to Busan and know each other better.