A 10 billion won insurance murder case causes Oh Ha Naui to lose everything. She sets out to take revenge upon Chun Mi Ja who caused her misfortune.
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."