Kim Ji-Hoon stars as a government investigator in 17th century Korea. Kim Hyung Do (Kim Ji Hoon), originally an ordinary inspector for the government, rises in the ranks due to his single-minded drive. Chosen for a secret organization within the government which investigates unexplained phenomena, he soon stumbles across a series of mysterious, supernatural events, and sets out to discover the truth behind them. In his quest he is helped (and sometimes hindered) by Heo Yoon Yi (Im Jung Eun), a government employee whose enthusiastic belief in the supernatural stands in stark contrast to his own cool-headed logic. Wonderfully filmed and suspenseful, this drama skillfully weaves together mystery, drama, and a little romance in a heady concoction of science fiction and historical intrigue.