Yu GangHyuk was only 7 years old when his father was murdered in a car "accident" and separated from his identical twin, Yu Shin-hyuk. He forgot his name and family and given the name Suh Ha-eun by his adopted father Suh Jae-soo. He falls in love with his adopted sister, Eun-ha and tried to be very honourable about it. He was led to become a cop because of his father’s badge. While investigating an alleged case of suicide, he eventually learns of his twin brother. Against the warnings of his peers, Ha-eun becomes more and more involved in this suspicious case. As a part of a larger scheme, Ha-eun is targeted for a hit by unknown individuals. And when Ha-eun and Shin-hyuk finally meet for the first time after twenty years, the murderers kill ShinHyuk accidently mistaken him for Haeun. As a result, Ha-eun vows to get revenge by giving his enemies psychological torture and takes on his brother's persona as an undercover cop and that is where the drama begins... This is a wonderful detective drama with a psychological twist.