Description：The story begins in the 1960s. In order to atone his sins, student movement leader Lee Ki-chul (Lee Jong-won) came to a remote mine and became a miner. In the process of fighting against the greedy and insidious mine owner Shin Tae-hwan (Cho Min-ki), Lee Ki-chul fell into the latter's trap and unfortunately died. Lee Ki-chul's eldest son Lee Dong-chul (Song Seung-heon) witnessed all this, and in grief, he vowed to avenge his father. At the same time, in order to avenge Shin Tae-hwan's abandonment, nurse Mi-ae switched Shin Tae-hwan and Lee Ki-chul's children. In this way, Shin Tae-hwan's child Myung-hoon (Park Hae-jin) became Lee Dong-chul's younger brother, and Lee Ki-chul's son Lee Dong-wook (Yeon Jung-hoon) grew up under Shin Tae-hwan's lap. As time went on, as Myung-hoon and Lee Dong-wook's complicated life experiences gradually surfaced, the two of them became increasingly confused.