The story is all about a corrupt yet practical detective who manifests asplit personality who harbours a sense of justice. Soo Yul (Lee Dong Wook)works as a police officer. He is competent at his job, but he also has questionable ethics. He will do anything to achieve success. Due to his ambitious personality, he has received promotions in a short period of time. His smooth life suddenly changes with the appearance of K (Wi Ha Joon). K is a righteous person, but also a crazy person. Whenever he faces injustice, he meets it with a fist. He dreams of being a hero. Meanwhile, Hee Kyum (Han Ji Eun)works as a police lieutenant on the drug squad at the Mooui Police Department. She is also a righteous person and enthusiastic at her job. She once dated Soo Yul.