Description
Three children of the Merrye family live in a decaying rural mansion with their protector and chauffeur, Bruno (Chaney). The children suffer from "Merrye Syndrome", a genetic affliction unique to members of their family, which causes them to mentally, socially and physically regress down the evolutionary ladder, starting in late childhood. Two distant relatives arrive with their lawyer and his secretary in order to examine and claim the property as rightful heirs. Bruno's shaky control over the children deteriorates; murder, chaos and insanity ensue.
The siblings, Ralph (Haig), Virginia (Banner), and Elizabeth (Washburn), are inbred, demented, and dangerous. These overgrown children exhibit playful innocence mixed with brutality and feral madness. Virginia is known as "Spider Baby" because of her obsession with spiders. She stalks and eats bugs, moving with a strange and spider-like grace. She also enjoys trapping unsuspecting victims in her rope "web", "stinging" them to death using two butcher knives. After murdering an innocent delivery man (Moreland), Virginia cuts off one of his ears, which she keeps in a match box.
Ralph is a sexually advanced, but mentally deficient simpleton who moves through the house via the dumb-waiter. Unable to speak, Ralph communicates with only grunts and leers. He becomes sexually aroused with the arrival of the two visiting women.
The mysterious Aunt Clara, Aunt Martha, and Uncle Ned, who have regressed even further than the Merrye siblings, live in the cellar. The skeleton of the family's dead father is kept in a bedroom and is kissed goodnight by Virginia.
Bruno, the children's sworn and loving protector, has been able to maintain control and keep the family secrets hidden. But when the snooping, greedy cousin Emily (Ohmart) and her brother Peter (Redeker) arrive to take possession of the property, the bizarre behavior of the Merrye clan is revealed.
Peter, Emily, their lawyer Schlocker (Schanzer), and his assistant Ann Morris (Mitchel) insist on staying at the house. Dinner is served after Ralph happily kills a cat for the main course. The revolting meal includes insects, mushrooms, and a garden salad made of weeds.
Virginia and Elizabeth murder Schlocker, eventually dumping his body into the basement, where the demented beastly relatives apparently eat him. Bruno leaves on an errand. Despite warning the children to "behave", events spiral downhill as the Merrye kids run amok. The basement dwellers are unleashed. Meanwhile, Emily models some black lingerie as Ralph peeks in. After being chased and then raped by Ralph, Emily becomes sexually aggressive and murderous.
Bruno returns and realizes that he has lost control of the children and of their secret unsavory lives. He lights a bundle of dynamite, blowing himself, the house and the children to bits. This seems to kill all carriers of "Merrye Syndrome".
Peter, who managed to escape the house with Ann, is recounting the story as the movie comes to a close. Addressing the audience, he explains that, as the sole remaining heir, he inherited the Merryes' vast family fortune, married Ann and wrote a book on the strange "Merrye Syndrome" phenomenon. He adds that his particular branch of the family was distant enough to be immune to the syndrome. However, the camera cuts to Peter's young daughter, who eerily resembles Virginia, admiring a spider in its web.
