Jung Won who finds life difficult while looking after her paralyzed mother and working a part time job, decides to kill herself. Soo Wan, who is trying to come to grips with the meaning of life after witnessing his mother commit suicide at a young age, works as a police officer. When the two meet in Chuncheon, they make a suicide pact.
Soo Jung has been with her boyfriend for 10 years, but their romance is now nothing but a lukewarm relationship. The night before her business trip to Busan, Soo Jung heard that her friend is getting married to her first love, and feels distracted. On the train to Busan, she sits next to Jae Hyun, who’s claiming himself as an Agapemonite, an obscure Christian sect where men took many spiritual brides, and that he will willingly jump into bed with a woman for one night. Falling for her gorgeous hips, he keeps coming on to her during the journey. She tries to push him away but ends up sharing a car ride to Busan with him due to the sudden breakdown of the train. She begins to slowly open up to him as he consistently tries to win her heart. And as the time passes on the road, she gets to see the true inside of Jae Hyun, hidden behind his featheriness and finds herself attracted to him.
When Ji Sung-Joon was young, he was ugly. As he grew up, he began to have an attractive appearance. When Kim Hye-Jin was young, she was pretty. As she grew up, she became ugly. Ji Sung-Joon tries to find his first love.