Busan in 1978, tells the story of Dong Zhu (played by Jang Dong Gun) from a poor family, Jun Shuo (played by Liu Wuxing), the eldest son of the underworld, and the hardworking The story of Shan Tai and his eloquent Rong He four good friends. Although Shan Tai ranks first in the school all year round, Dong Zhu and Jun Shuo always get into trouble and become problem students in the school, but the friendship between the four of them remains unwavering. But then Dong Zhu and Jun Shuo were expelled from the school in order to stand up for Shan Tai, and the three gradually lost contact.
Seoul in 1984, Shan Tai and Rong He have gone to college and started to look for Dong Zhu and Jun Shuo who have lost contact for a long time, but they have already joined the underworld, one is in jail and the other is in drug rehabilitation. During this process, Shan Tai and Rong He began to reflect on their past, and gradually discovered the preciousness of friendship.
In the autumn of 1990, Shan Tai, who studied in the United States, returned to China for vacation, and returned to the past life, feeling deeply about the past friendship . However, Dong Zhu and Jun Shuo became real enemies during the gang fight. In the face of such a situation, how should the four of them face the conflict between the former friendship and reality?
This movie depicts the friendship and reflection on reality between four good friends in different time periods. Although they have embarked on different paths, their perception of friendship has changed at different stages. This story tells us that friendship is priceless, and we should cherish those around us, and reflect on our choices all the time in our lives.