Abandoned towers of a fearsome warrior civilization and a castle that was once a fairy-tale estate are now haunted ruins; experts investigate the secrets behind these desolate fortresses to uncover how they were built and why they were abandoned. This is a mashup of S05E03 "Haunting of Heartbreak Castle," S06E07 "Towers of Blood," and S07E05 "Factory of Death." 

Long, dome-like structures camouflaged by a rural landscape conceal the remains of concrete vaults with a hidden history; experts investigate and uncover state-of-the-art bunkers built to conceal and protect a deadly nuclear secret.