Detective K Secret Of The Lost Island is the story of Detective Kim Min Joseon. In 1795, a large number of fake silver is falling into circulation to create a significant threat to the economy. Detective Kim Min is tasked with investigating the perpetrators behind the incident and inadvertently lifts the veil of mystery about fake silver production. A problem they need to solve immediately is the distribution of these large number of fake silver. This time also with his intelligence, Kim Min with his partner - Seo Pil find out the trurth.