America's greatest unsolved mysteries are explored through interviews, archival footage and re-creations. Recently unearthed evidence and intriguing new theories bring each case closer than ever to finally being solved.
Experts investigate disturbing phenomena at Skinwalker Ranch, top-secret experiments may have been conducted at a former Air Force base in Long Island, New York, and new theories could explain why Mount Shasta is a magnet for paranormal activity.
Shocking new theories about the Mantell incident are revealed, scientific evidence may explain a UFO encounter in Texas and experts investigate what really crashed into a Canadian harbor.
Newly declassified documents could link the Roswell crash to Nazi science, fresh evidence may reveal what's really hidden inside Area 51 and experts investigate the dark secrets of the Dugway Proving Ground.
Experts investigate the abduction of Betty and Barney Hill, recent new evidence could explain where Travis Walton was for five days and there may be an earthly explanation for the Mothman.
Experts may have finally identified the strange creatures that besieged a Kentucky farmhouse, new evidence could explain the largest mass UFO sighting in US history and investigators seek answers in Chicago's O'Hare International Airport sighting.
Experts investigate the mystery of the Bermuda Triangle, researchers seek answers about strange sightings in Massachusetts and a crazed murderer may be responsible for a string of unexplained disappearances in Bennington, Vermont.