The story takes place in Seoul, 2011. Lee Yoon-sung is a talented MIT-graduate who's working on the international communications team at the Blue House. He encounters dangerous situations while solving a variety of cases, both big and small, for people who need his help, and eventually becomes a "city hunter."
Ma Hye Ri is a woman with an excellent memory and ability to focus, which allowed her to pass the bar exam with ease. Despite her talents, she is more interested in being fashionable and dislikes hard work, so she is far from being an ideal prosecutor and has doubts about her suitability for her job. Through her conflicts with senior colleagues and struggles with difficult cases, however, Hye Ri gradually matures into a brilliant prosecutor with a sense of duty and justice.
This drama portrays the turbulent life of Lee Mi Reuk, a Korean expatriate who fought for the freedom of his country while studying medicine in Tokyo, during the period when Korea was under Japanese colonial rule. He fled to China and eventually settled in Germany.