In New York City, during a séance held in the apartment of medium Theresa, Mary Woodhouse (Catronia MacColl) experiences a traumatic vision of a priest, Father Thomas (Fabrizio Jovine), hanging himself from a tree branch in the cemetery of a remote village called Dunwich. When the images overwhelm her, Mary breaks the circle, goes into convolutions, and falls to the floor as if dead. The police, led by Sergeant Clay, interrogate Theresa, but fail to heed her warnings of an imminent evil. Outside the apartment building, Peter Bell (Chirstopher George), a local journalist, tries to gain entry to the premises but is turned away. The following day, Mary is buried in a local cemetery on Long Island overlooking Manhattan and Peter visits her grave site. The gravediggers (Perry Pirkanen and Michael Gaunt) leave Mary's half-covered coffin at the end of their work shift and leave. Soon, Peter hears muffled screams as he reluctantly leaves the graveyard. Using a pickaxe, he frees the screaming woman from her premature burial, but with the pickaxe coming dangerously close to her head as it smashes through the casket lid.Peter and Mary visit Theresa where she warns them that according to the ancient book of Enoch, the events Mary has witnessed in her visions presage the euroption of the living dead into our world. The death of Father Thomas, a marked priest, has somehow opened a door through which the living dead can enter and the invasion will commence on All Saints Day, just a few days away.In Dunwich, Bob (Giovanni Lombardo Radice), a lonely youth with a bad reputation, wonders into a desolate, empty house. He finds a rubber doll which inflates itself. But before he can use it, the sight of a rotting babys corpse scares him away. At Junie's Lounge, the barman discusses recent events with two local men, Mr. Ross (Venantino Venanini) and Mike. Strange events have been occurring the last few days, and Mr. Ross is inclined to blame Bob. When a mirror shatters and the wall cracks inexplicably, the men leave, despite the bartender's offer of free drinks. Across town, Gerry (Carlo De Mejo), a psychiatrist, is in consultation with Sandra (Janet Agren), a neurotic patient, when Emily Robbins (Antonella Interlenghi), his 19-year-old girlfriend and personal assistant, arrives. She tells Gerry that she's on her way to meet Bob, whom she has been trying to help. After Emily leaves, Sandras pet cat, whom she has been holding through her session, suddenly scratches her badly on her hand, and huddles in a corner. That evening, Emily visits Bob at a disused garage, but unearthly groans scare him away. Emily is left alone when she faces the supernatural apparition of Father Thomas who smothers her with a maggott-covered hand.A short distance away, Rose Kelvin (Daniela Doria) and Tommy Fisher (Michele Soavi), a teenage couple, are making out in Tommys jeep near the vicinity when they too face the ghostly image of Father Thomas outside the jeep. With a powerful, mesmerizing stare, Father Thomas makes Rose's eyeballs bleed and she meets a ghastly fate by vomiting her entire guts out while Tommy watches, and he is immediately killed by getting his head ripped open by an unseen ghoul. The next morning, there is no sign of Rose or Tommy, while Emily's body is found at the garage. The local pathologist Dr. Joe Thompson (director Lucio Fulci), cannot make a clear assumption to how Emily died except from a heart attack caused by shear fright. After Dr. Thompson leaves the scene, Sheriff Russell finds a small puddle of black, worm-infested fluid nearby. Mr. Robbins tells the sheriff and Gerry of his suspicious about Bob. Meanwhile, Peter and Mary leave New York and embark upon their search for the town of Dunwich, as seen in Mary's vision.As All Saints Day approaches, the people of Dunwich suffer further ghostly visitation in advance of the Hellish outpouring. That evening, Bob sees Father Thomas hanging in the deserted house he frequents. At the local morgue, a mortician is bitten on his hand by the cadaver of a old women, called Jane Holden, whilst trying to steal her jewelry. The apparition of the dead Emily pays a nocturnal visit to her little brother John-John (Luca Paisner). At Sandra's house, the corpse of Mrs. Holden appears without explination on her kitchen floor. Sandra calls Gerry for help, and he tries to cling onto the possibility of a rational explination. But as soon as Gerry arrives, the body has disappeared as mysterious as it appeared. Investing noises upstairs in Sandra's house, the doctor and patient witness broken glass fly from a shattered window into the wall opposite. The wall bleeds before their eyes, forcing them to flee the house. Meanwhile, Bob has taken refuge at the Ross household in the garage. When Mr. Ross's teenage daughter finds him and tries to comfort him after he tries to explain whats going on outside, the rabid patriarch enters, and mistakenly assuming that Bob is trying to seduce his daughter. The vicious Mr. Ross kills Bob in a horrific way by impaling his head on a drilling lathe.The following morning, Peter and Mary follow a bland village priest's directions to the shunned village of Dunwich. Arriving at the graveyard, they begin searching for Father Thomas' tomb. Gerry and Sandra also arrive after following a trail there, and the two couples exchange stories about their recent events. They begin to become acquainted at Gerry's office when a sudden violent storm blasts through the window, showering the four with maggots. When it's over, Gerry receives a distressing phone call from John-John Robbins. The little boy says that his dead sister has returned from the grave during the night and killed his parents. The four rush over the Robbins' house and find that John-John's story is true. Sandra offers to take the boy to her apartment while, Peter, Mary, and Gerry try to find the sheriff. Upon arriving at the entrance to Sandra's apartment building, she is killed by the malevolent zombie/ghost of Emily, who rips Sandra's scalp off. John-John runs through the fog-shrounded streets of the town, evading more zombies of the townspeople, when he is saved by Gerry who hands the boy over to the police.At Junie's Lounge, Mr. Ross, Mike, and the barman are attacked and finally killed by the marauding ghouls as a state-of-emergency is declared over the radio. Mary, Peter, and Gerry arrive back at the graveyard as All Saints Day begins. They decent into Father Thomas' family tomb, discovering an underground grotto of skeletal remains and cobwebbed putrescenes. Sandra appears as a zombie, and kills Peter by ripping his brains out. The zombie Sandra is then immobilized by Gerry who impails her to a cave wall with a pitchfork to her chest. Mary and Gerry are forced to go on until they reach a weired, stained-glass chamber coated in musk and dust. There, they face Father Thomas who has re-entered corporeal existence with his supernatural powers intact. Mary and Gerry look on as all of the dead begin to emerge from their tombs and surround them. Father Thomas once again begins to use his powerful and mesmerizing stare making Mary's eyeballs bleed. Before his stare can turn Mary inside out, Gerry grabs a large, rotting, wooden cross and disembowels Father Thomas. The evil priest's decayed guts are punctured, and he and the massing zombies burst into flames and return to dust. The Gate of Hell have apparently been closed. Mary and Gerry struggle from the subterranean catacombs of the night and emerge back out of Father Thomas' tomb into the graveyard at morning, to see John-John running excitedly towards them. As he approaches, Mary and Gerry's joy turns to disquietude, and then to fear, until the movie suddenly ends as ambiguously as it began... with Mary's scream.
Output: Question: The invasion of the living dead will happen on what day?, Answer: All Saints Day