Minister Piljoon Song has flooded Korea with counterfeit currency, using the ensuing chaos resulting from massive inflation as a springboard for demolishing the confidence of the Emperor's reign, aiming to take power in the aftermath. He is aided by the skilled swordsman, Sad Eyes, who comes up against the police force investigating the funny money, with detective Namsoon and her grizzled partner detective Ahn proving his most formidable adversaries. On her mission to gather evidence against Piljoon, Namsoon clashes with Sad Eyes again and again, but their heated duels result in much more than just admiration.
A tomboyish detective by the name of Nam Sun (Ha Ji Won, from Love So Divine and Phone) who ends up being assigned to investigate a case revolving around some counterfeit coins. Going deep undercover in a variety of diverse disguises, Nam Sun quickly finds herself chasing after a notorious assassin named Sad Eyes (Kang Dong Won, from Too Beautiful to Lie and Romance of Their Own), who just may be involved in the crime she's investigating.