"Tracer" is a thrilling chase and fighting drama about a vicious guy who parachuted into the National Tax Service's Tax Bureau 5, which is more terrifying than judges and prosecutors, also known as the "garbage dump" for some people, and gallops recklessly. Im Siwan ([The Attorney, Misaeng]) plays Hwang Dong-joo, the newly appointed team leader of the 2nd Section 1 Group of the Seoul Investigation Bureau 5. He is very good at getting along with everyone and stands out with his unique ability to be sharp-tongued. Ko Ah-seong ([The Host, Life on Mars]) plays Seo Hye-young, an investigator of the Tax Bureau 5. She has a more accurate intuition and investigation ability than ordinary people, and is more active than anyone else and leads the entire team. Son Hyun-joo ([Secretly Great]) plays Eun Tae-joon, the former director of the Investigation Bureau of the National Tax Service and the current director of the Seoul Local National Tax Service. He has a sharp mind and excellent workplace judgment, and always maintains a dignified and arrogant attitude. Park Yong-woo plays Oh Young of the Investigation Bureau 5. He used to be the ace of the Tax Bureau and was very active, but now he is no longer the same. The drama is directed by Lee Seung-young and written by Kim Hyun-jung ("Manipulation").