In this Joseon-era alternate history strange, possibly alien phenomena are secretly recorded by people within the government. Heo Yoon Yi is a government employee who aids him and attempts to understand these scientific impossibilities with an open mind, in contrast to his cynicism.
Kim Hyung Do is an inspector of the state whose single-minded focus on his investigations into administrative misdeeds bring him into direct contact with these strange mysteries. Joseon X-Files: Secret Book is based on cases detailed in the Annals of Joseon History with a bizarre twist these incidents incorporate mysterious, supernatural elements that cannot be explained through science.
