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...
When the villagers of Klineschloss start dying of blood loss, the town fathers suspect a resurgence of vampirism. While police inspector Karl remains skeptical, scientist Dr. von Niemann cares for the vampire's victims one by one, and suspicion falls on simple-minded Herman Gleib because of his fondness for bats. A blood-thirsty mob hounds Gleib to his death, but the vampire attacks don't stop.
Young couple Madeleine and Neil are coaxed by acquaintance Monsieur Beaumont to get married on his Haitian plantation. Beaumont's motives are purely selfish as he makes every attempt to convince the beautiful young girl to run away with him. For help Beaumont turns to the devious Legendre, a man who runs his mill by mind controlling people he has turned into zombies. After Beaumont uses Legendre's zombie potion on Madeleine, he is dissatisfied with her emotionless being and wants her to be changed back. Legendre has no intention of doing this and he drugs Beaumont as well to add to his zombie collection. Meanwhile, grieving 'widower' Neil is convinced by a local priest that Madeleine may still be alive and he seeks her out.