A mad scientist, who discovered the secret of eternal youth by draining of blood from a young woman, gets executed. His ancestor moves into the home, eventually discovering the scientist's body. He revives him, and the terror continues.
People are mysteriously disappearing near a remote Cornish village, where a scientist is experimenting with reviving the dead.
Dr. Henry Jekyll experiments with scientific means of revealing the hidden, dark side of man and releases a murderer from within himself.
Aliens from a dying world plot to conquer Earth by preying on man's superstitions. Bringing two dead scientists back to life, they use their knowledge to re-animate various monsters, including the werewolf Waldemar Daninsky, Frankenstein's monster, the mummy Tao-Tet, and the vampire Count de Meir...