Despite their different family backgrounds, four friends grew up together in the wearisome years of the 70s. But as time goes by, each of them takes a different life path.

Joon-seok is sent to prison for his involvement in Dong-soo's death. He meets Dong-soo's son in prison, keeps his identity a secret, and agrees to join forces when he is released. All of their plans fall apart when Sung-hoon finds out the truth.