Set in the last dynastic period of Korea, Han Se-kyu is a royal investigator of the palace and son of the Right State Minister. Known throughout the capital, Hanseong, as an illustrious and just investigator, who has solved many mysteries throughout the city. Han Se-kyu is tipped by a young woman that there is some suspicious activity surrounding the Left State Minister. Han Se-kyu takes on the challenge of solving the crimes masked by corrupted palace officials.