Jang Choon-dong is a traffic officer who aspires to become a homicide detective. He is assigned to go undercover to infiltrate a gangster network. Meanwhile, Lee Joong-dae, a member of Kwang-seob's gang, goes undercover himself by joining the police force. Joong-dae tries hard to gain favor with his squad leader in an effort to expose Choon-dong's identity.
| Actor | Role |
|---|---|
 Jung Jun-hoJang Choon-dong | Jang Choon-dong |
 Jung Woong-inLee Joong-dae | Lee Joong-dae |
 Jung Woon-taekMoon Dong-sik, aka Dae Ga-ri | Moon Dong-sik, aka Dae Ga-ri |
 Han Go-eunCha Se-rin | Cha Se-rin |
 Kim Sang-joongAhn Kwang Seop | Ahn Kwang Seop |
 Sunwoo Jae-dukSquad Leader Park Jong-ki | Squad Leader Park Jong-ki |
 Jeon Mi-seonPark Jong-ki's wife | Park Jong-ki's wife |
 Park Sang-minSsang-kal | Ssang-kal |
 Yoon Hae-youngJo Min-ju | Jo Min-ju |
 Yu Da-eunDisguised Female Detective | Disguised Female Detective |
 Jung Kyung-hoonWorker 1 | Worker 1 |
 Kim Dong-seokExecutive Police 2 | Executive Police 2 |
 Kang Dong-gyunCommando #1 | Commando #1 |
| PPark Yong-giCheon Seong-gi | Cheon Seong-gi |
 Kim Dae-heeWon-sam | Won-sam |
 Ji Dae-hanAx | Ax |
 Jo Han-sunMotorcycle | Motorcycle |
 Kim Heung-gukTraffic violator | Traffic violator |