Busan in 1978, Dong Soo ( Jang Dong Gun ) is a child of a poor family, Junshuo (Yoo Wuxing) is the son of the boss of the Underworld Society group, the especially hardworking San Tai and the especially good-natured Rong He. San Tae often takes the first place in the school, while Dong Soo and Jun Suk are troublemakers everywhere, but the four of them are good friends. Dong-soo and Jun-seok, who later entered middle school, were expelled from the school for taking the lead for San-tae.
In Seoul Special City in 1984, Shan Tai and Rong He, who entered the university, searched for the whereabouts of two friends , but these two friends have now joined the Underworld Society. One is in jail, the other is in rehab.
In the autumn of 1990, Shantai, who was studying in the United States, returned to China for a vacation, lamenting the old friendship. Due to their mutual revenge in the gang fight, Dong-soo and Jun-suk have become real enemies, how should they face their former Friend?
