The film stars Jun Ji-hyun as Officer Yeo Kyung-jin, an ambitious young female police officer serving on the Seoul police department. One day while chasing a purse snatcher, she accidentally captures Go Myung-woo (played by Jang Hyuk), a physics teacher at an all-girls school, who was actually trying to catch the thief. Later, Myung-woo discovers the stolen purse, but just as he picks it up, Kyung-jin spots him and tries to arrest him again. Kyung-jin is then given the job of escorting Myung-woo through a dangerous district, only to be distracted when she tries to break up a meeting between Russian Mafia and Korean gangsters. With Myung-woo handcuffed to her, Kyung-jin almost single-handedly brings down the two rival gangs (although she is helped when she accidentally causes the groups to start shooting at each other).