A young man must escape from a mysterious locked vault before he dies of dehydration.

Twelve year old Ryan Billings has been diagnosed with an acute fear of the dark. He spends each night lying awake in torment, waiting and watching as the evil in the darkness grows stronger, feeding off his fear. His older brother Dale, suspects that there is nothing wrong with Ryan and that this is just a ploy for more attention. Regardless, he promises to watch over his little brother as their parents head off to a party for the night. Outside a storm rages and when the power goes out, darkness envelops the house. Ryan knows that tonight the evil has finally come to claim him. Dale desperately tries everything to try and calm him down, until the horrors in the dark make him realize Ryan had good reason to be so afraid!

Kerwin Matthews, playing a dissolute drifter down on his luck, is stranded in a cheap bar in France where he falls for Annette, the pretty daughter of the proprietor, played by Nadia Gray. Nadia Gray gradually shifts the young man's attentions to herself, rather than her daughter, and together Matthews and Gray concoct a plot to help Gray's estranged husband, now a homicidal maniac confined in an institution after a grisly series of killings dubbed "The Acetylene Murders" by the press, out of the mental institution so he can escape from the country.