Rumors of UFO sitings and human disappearances in a remote section of Mexico draw a man and woman team of magazine photographers to investigate. The police commandante attempts to dissuade them from venturing into the mountains, then, failing that, refers them to a local man to be their guide - the brother of the only person confirmed to have really disappeared. Once among the hills, this trio discovers strange lights in the skies, an abandoned rifle with a grotesquely twisted barrel, something moving in the underbrush...