Jang Do-young is a tough, short-tempered, somewhat jaded homicide detective. Most members of his department regard him as a troublemaker and he has lost faith in the system. Jang has been struggling to nail Yoo Kang-jin, a notorious crime boss, with little success so far.

Jang crosses paths with Oh Jin-woo, an elite prosecutor who graduated at the top of his class and who lives his life by the letter of the law. To Oh there would be no civilization without rules. Oh is also on a mission to bring Yoo to justice. He had managed to get Yoo put in jail some time ago, but the gangster got out early and is now preparing to run for political office. Oh thinks he ought to re-investigate Yoo; he’s convinced there is enough evidence to put him away for good. So he and Jang form an uneasy alliance.

When Yoo learns of this new threat, he decides to show them what they’re up against. He gets his henchmen to attack Jang’s family and he arranges to have Jang and Oh arrested for police harassment. The fight has now become personal. For Jang and Oh, it is no longer a matter of simple justice; whether they’re prepared to admit it or not, the war with Yoo has become a matter of survival and revenge.