"Detective K" is the greatest Joseon detective story ever told about a private eye who is part clumsy and part genius with slyness and wit as his weapon. In 1795, the nineteenth year of King Jeongjo’s reign, a large amount of fake silver is slipped into circulation creating a substantial threat to the economy. Detective Kim Min is assigned the task to investigate the crime ring behind the scheme. He goes undercover in a rural village with his best friend and sidekick, Seo-Pil. In the village, the pair meets a girl called Dahae who asks them to help her find her missing sister. Soon, Dahae goes missing, too, and discolored, bluish corpses of village girls begin to wash up on the shore. Kim Min discovers that these deaths are directly related to the manufacturing operation of counterfeit silver.