A group of scientists have developed the Resonator, a machine which allows whoever is within range to see beyond normal perceptible reality. But when the experiment succeeds, they are immediately attacked by terrible life forms.
Shortly after delivering a patient to an understaffed hospital, a police officer experiences strange and violent occurrences seemingly linked to a group of mysterious hooded figures.
A boating accident runs a young man and woman ashore in a decrepit Spanish fishing town which they discover is in the grips of an ancient sea god and its monstrous half human offspring.