Synopsis: Townspeople are found dead, drained of their blood, leaving terrified villagers powerless against an unseen menace. The authorities are unable to explain the ferocious killings and a superstitious fear of bats grips the countryside. A kindly professor, unaware of the malevolent spirit that dwells within his own heart, undergoes a hideous transformation into a demonic vampire with an insatiable lust for blood. Only his hunchbacked assistant knows of the professor's dark secret as the murders increase and a cry for vengeance arises.