A collection of historical mystery investigations pulls together several unsolved cases, anchored by the 130-year-old riddle of Thomas Beale, who claimed to have buried a fortune in the Blue Ridge Mountains and left behind ciphers that treasure hunters still cannot fully crack. Researchers and historians walk through the ciphertext, the competing decoding attempts, and the deaths and ruined lives some blame on the search. Elsewhere the film turns to the search for Camelot, weighing the archaeological sites in Britain that have each been proposed as Arthur's court and testing what, if anything, separates legend from a real Dark Age stronghold. Experts appear on location and in interview, tracing manuscripts, maps, and excavation reports rather than simply retelling the myths. The format moves between cases rather than resolving any single one definitively, treating each mystery as still open and letting specialists disagree on camera about what the evidence actually shows.