A documentary filmmaker turns his lens on an enigmatic conspiracy theorist who claims he's found the entrance to a vast underground city populated entirely by monsters. A documentary filmmaker turns his lens on an enigmatic conspiracy theorist who claims he's found the entrance to a vast underground city populated entirely by monsters. A documentary filmmaker turns his lens on an enigmatic conspiracy theorist who claims he's found the entrance to a vast underground city populated entirely by monsters. A documentary filmmaker turns his lens on an enigmatic conspiracy theorist who claims he's found the entrance to a vast underground city populated entirely by monsters.