Dr. Paul Carruthers is frustrated because he thinks his employers, Mary Heath and Henry Morton, have cheated him out of the company's profits. He decides to get revenge by altering bats to grow twice their normal size and training them to attack when they smell a perfume of his own making. He mixes the perfume into a lotion, which he offers as a gift to Mary and Henry. When they turn up dead, a newspaper reporter decides to investigate.
A scientist keeps his wife young by killing, stealing the bodies of, and taking the gland fluid from virgin brides.
On the beach one night, Christine Faber, two years a widow, thinks she hears her late husband Paul calling out of the surf...then meets a tall dark man, Alexis, who seems to know all about such things. After more ghostly manifestations, Christine and younger sister Janet become enmeshed in the eerie artifices of Alexis; but he in turn finds himself manipulated into deeper deviltry than he had in mind...
After several locals are viciously murdered, a Louisiana sheriff starts to suspect he may be dealing with a werewolf.