Lonely lighthouse-keeper Sturges (John Harmon) keeps mostly to himself, doing his job, which includes warning people away from the beaches and caves near the Piedras Blancas lighthouse. But when two fishermen are found dead, all-but-beheaded and without a trace of blood in their bodies, that brings Constable Matson (Forrest Lewis) and Dr. Jorgenson (Les Tremayne) snooping around. And suddenly the village is being stalked by some kind of monstrous creature, capable of killing anyone in its path. Sturges reveals what he knows, but this may be too late to save his daughter Lucy (Jeanne Carmen) or himself.