Description
George is taking a trip from his antique shop in Manchester to the Lake District to work on a new house with some of his friends. On the way, his Norton motorcycle is accidentally damaged by Edna while reversing her Mini Cooper at a petrol station. He demands she give him a lift to his destination, while Edna, on her way to visit her troubled sister, asks to go to the town of Southgate first, and to let George take her car to Windermere where she will later retrieve it.
George agrees, but the two come to a dead end road alongside a river while searching for Edna's sister's house. George crosses the river on foot to a farm where several men from the Ministry of Agriculture are using an experimental machine in a field. While asking for directions, he inquires about their machinery, which they explain is designed to kill insects through ultra-sonic radiation. Meanwhile, while Edna waits at the car, she is attacked by a man who emerges from the river, but he disappears after she reaches George.
Night falls, and Edna's drug addict sister, Katie, is getting into an argument with her photographer husband, Martin, about her sister's impending arrival. Martin goes down to a waterfall near their remote cottage to take photographs, and Katie is attacked by the same man who Edna had encountered earlier. The man kills Martin, and Katie flees just as George and Edna arrive. When the three report the death, the aggressive police sergeant thinks that Katie did it. George, forced to stay in Southgate, secretly takes the roll of film from Martin's camera to a local chemist to have it developed. Katie has a breakdown and is hospitalised. At the hospital, it turns out that babies are affected too, biting people with homicidal intensity.
Back at the chemist's, they collect the photos, but the dead man does not appear in any of the pictures; the man, it turns out, is a local vagrant who drowned in the river. The sergeant arrives and takes photos and, when the couple leaves, sends one of his officers, PC Craig, to trail them. They go to the graveyard and in a room in the chapel find a half-eaten meal. Following noises to a crypt, they come across a murdered man and are locked in by the vagrant zombie, who brings the other bodies to life by touching their eyes with his blood-stained fingers. The pair manages to make a hole they can escape from and Edna does, only to find herself in a pit while the zombies have hold of George's feet. Meanwhile, PC Craig turns up and helps Edna out of the pit. George manages to get free and follows them, with the zombies chasing all three of them. They lock themselves in a room but are trapped there, and Craig soon finds that his gun is of no use. He makes a dash for the police radio he has dropped outside but is caught by the zombies who eviscerate him and begin eating his organs.
The dead break into their room and in desperation George throws a lit oil lamp at them. It smashes and the zombies burst into flame. The two escape to their car and Edna is sent off to tell the police. George plans to use the unmarked police car to go and smash the machine but it has no key so he runs off. At the machine, the farmer and two machine men do not believe George and reveal that the machine is now working up to a five miles radius. They try to stop him, but he smashes the machine and they drive off to get away from "the mad man".
The sergeant has found Craig and the caretaker's bodies, and thinking they may be devil worshippers, issues orders "to shoot to kill" George and Edna. He is then told that George has deliberately wrecked the machine. Edna has arrived at her brother-in-law's farm only to be met by Martin, who is now a zombie, but she manages to run over him as she escapes. George finds her, drops her off at a petrol station and drives off with a large can of petrol. George is caught in a police trap and Martin's body is taken back to the hospital.
In a field, the machine is repaired and switched on again, which brings to life a number of bodies in the nearby morgue. George escapes in a police car and finds Edna has been taken to the hospital, where the local morgue is. She is being sedated while George is now being chased by the police as he drives to the hospital where the zombies are now killing people, including Katie who as a zombie tries to kill her sister.
George arrives and starts setting fire to zombies but it turns out that he was too late to save Edna and as she suddenly attacks him, he pushes her into a room, which is now burning. George is then shot four times by the over-zealous police sergeant. Everything is over as far as he is concerned now and the sergeant heads to a room at the hotel in South Gate for the night. After shooting him down in cold blood, the sergeant wishes he would come alive again so he could shoot him again. He gets his wish as zombie George is waiting for him in his room, but now bullets won't stop him. In a field nearby, the machine continues working.