A desolate fortress in a secluded mountainside and the remnants of a town in the backwoods of Kentucky are now ghostly ruins; experts investigate the secrets of these remote, rural mysteries to uncover how they were built and why they were abandoned. This episode is a mashup of S07E06 "Ghosts of Black Mountain," S06E08 "The Thing of Hell Mountain," and S04E09 "Haunting on Plague Island."