A cousin stays overnight at a couple's place as both of her parents are missing. The husband suspects that she is a vampire as he keeps seeing corpses and her biting into them in his nightmares. Suddenly he becomes a vampire and hell breaks loose and must find a way to put an end to this.
When his experiments into a powerful new anesthetic go hideously awry, respected physician Dr. Jekyll transforms into the hideous Jack Hyde. As his wife Elisabeth passes her time in charitable work, rehabilitating the district's fallen women, Hyde is drawn into an escalating cycle of lust and murder that seems to know no bounds.