When Lee Dong Chul was five years old, his father was killed. He witnessed who the killer was and promised to seek revenge on the man who caused his father's death, Shin Tae Hwan. But unbeknownst to everyone is the fact that Dong Chul's younger brother, Dong Wook, was switched at birth with Tae Hwan's son, Myung Hun, in the hospital. Dong Wook grows up with dreams of becoming a prosecutor to help the family seek revenge on Shin Tae Hwan. But what happens when they find out that they're not brothers? What will Dong Chul do when he finds out that his real brother was raised by Shin Tae Hwan and that the brother that had been beside him all these years is actually the son of his enemy?