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.

Ruth Earlton has come home to her ancestral mansion to claim her inheritance. Accompanied by her boyfriend, she discovers that her father died suddenly under suspicious circumstances. Now it's her turn, as her deranged and relentless uncle targets her for death with the help of his wife and son, plus a very unhappy ape.