In a bizarre but fascinating bit of casting, Humphrey Bogart stars as a vampire in his only horror film role. After a murderous doctor is executed, he is revived with human blood-and soon people with that blood type begin to disappear. When an eager reporter stumbles across a popular actress who was thought to be dead, he can't help noticing that her skin is unnaturally pale and that she keeps her face concealed beneath a long black veil. Suspecting that evil is afoot, he investigates the terrifying world of a psychotic doctor (Bogart) and is drawn into a series of unsolved murders.