Hae-woong an assembly member candidate, is taken out of the running because he became a thorn in the side of a local bigwig, Soon-tae. Hounded by loan sharks, due to defaulting a campaign loan, he decides to get his hands dirty.

After barely surviving a violent attack by an elusive serial killer, crime boss Jang Dong-su finds himself forming an unlikely partnership with local detective Jung Tae-seok to catch the sadistic killer simply known as "K".