Yu Gang Hyuk 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 honorable 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 in twenty years, the murderers kill Shin Hyuk accidentally mistaken him for Ha Eun. 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.