In the late Joseon Dynasty, counterfeits are circulating around. Detective Ahn (Ahn Sung-Ki) of Left Security Station and passionate newcomer Namsoon (Ha Ji-Won) try to trace the source of the counterfeiting. They chase the Secretary of National Security and his man Sad Eyes (Gang Dong-Won]) as suspects. A predestined battle between the best female detective in Joseon, Namsoon, and mysterious assassin Sad Eyes unfolds ...