When his brother disappears, Robert Manning pays a visit to the remote country house he was last heard from. While his host is outwardly welcoming, and his niece more demonstrably so, Manning detects a feeling of menace in the air with the legend of Lavinia Morley, Black Witch of Greymarsh, hanging over everything.
In an ancient castle, a mad scientist is trying to revive his dead daughter by an operation, but there are certain body parts he needs that he can't get. His problem is solved when a group of drunken party-goers stumble into his castle.
In a dilapidated rural mansion, the last generation of the degenerate, inbred Merrye family lives with the inherited curse of a disease that causes them to mentally regress from the age of 10 or so on as they physically develop. The family chauffeur looks out for them and covers up their indiscretions. Trouble comes when greedy distant relatives and their lawyer arrive to dispossess the family of its home.
A misguided scientist enables an alien from Venus named Zontar to come to earth in order to "help solve man's problems". However, as soon as Zontar arrives on Earth, it quickly becomes obvious that the three-eyed, bat-winged, skeletal black creature has a hidden agenda.
Dracula travels to the American West, intent on making a beautiful ranch owner his next victim. Her fiance, outlaw Billy the Kid, finds out about it and rushes to save her.
Beautiful young manicurist Carole suffers from androphobia (the pathological fear of interaction with men). When her sister and roommate, Helen, leaves their London flat to go on an Italian holiday with her married boyfriend, Carole withdraws into her apartment. She begins to experience frightful hallucinations, her fear gradually mutating into madness.
Five strangers board a train and are joined by a mysterious fortune teller who offers to read their Tarot cards. Five separate stories unfold: An architect returns to his ancestoral home to find a werewolf out for revenge; a doctor discovers his new wife is a vampire; a huge plant takes over a house; a musician gets involved with voodoo; an art critic is pursued by a disembodied hand.
Experimenting in hypnotic regression to past lives, Dr. Edmund Redding of the Cowan Institute in Pasadena has discovered that Ann Taylor is a reincarnated Aztec woman. Via her recovered memories, she is able to lead Redding and his associates to a hidden chamber in the Great Pyramid of Yucatan, where they hope to find the lost treasure of the Aztecs. Instead, they find two mummified bodies - one of a modern man, quite dead, and the other of an ancient Aztec, quite alive. They are able to return safely to Pasadena with both finds, but a rival professor, Janney, kills Redding and steals the body of the modern man-mummy. This he subjects to a resurrection experiment, which works - only the mummy proves to be a werewolf. Two supernatural menaces roam the city that night. This film is composed of footage from two unrelated Mexican horror movies, LA CASA DEL TERROR and LA MOMIA AZTECA, plus new footage shot in the U.S. by Jerry Warren.
A widow deceives her late husband's mother and brothers into thinking he's still alive when she attends the yearly memorial to his drowned sister, hoping to secure his inheritance, but her cunning is no match for the demented, axe-wielding thing roaming the grounds of the family's Irish estate.
Lt. Andre Duvalier awakens on a beach to the sight of a strange woman who leads him to the gothic, towering castle that serves as home to an eerie baron.
After an unusual meteor shower leaves most of the human population blind, a merchant navy officer must find a way to conquer tall, aggressive plants which are feeding on people and animals.
Mary Henry ends up the sole survivor of a fatal car accident through mysterious circumstances. Trying to put the incident behind her, she moves to Utah and takes a job as a church organist. But her fresh start is interrupted by visions of a fiendish man. As the visions begin to occur more frequently, Mary finds herself drawn to the deserted carnival on the outskirts of town. The strangely alluring carnival may hold the secret to her tragic past.