A witch runs through the woods, pursued by men with torches. Her leg catches in a mantrap and she is taken away and tied to a stake. Lord and Lady Garrick are informed of her capture and go to watch her execution. As a man approaches to light the pyre around her, the witch invokes Satan and the man himself catches fire, burning to death before the assembled crowd. Lord Garrick runs back to his house, where he is strangled by a disembodied hand inside the wall. Lady Garrick follows him and his bloody body falls onto her from above. The witch appears and severs Lady Garrick's head with a sword, uttering a curse on the family line.

As the film ends, the lights go on and the spectators relax. They are guests at a house party given by James Garrick, descendant of the characters portrayed in the film; he claims that the events portrayed tell the history of his family, but some of his friends are sceptical. One of them, Gary, hypnotises Ann, James's cousin; in a trance, she attacks James using the sword used in the film, which also allegedly killed his ancestors. Coming out of her trance, Ann runs from the house.

Another guest, Carol, leaves the party and sets off home. Outside, she is chased by an unseen figure with a knife and stabbed. As Gary leaves, he finds her dead body impaled on a tree. Ann arrives back at her hostel and her roommate, Suzy, sees her washing blood off her hands.

James Garrick is at the film studio he owns, which is mobbed by press reporting on the murder. A director is there making a soft porn film featuring Viv, who lives at the same hostel as Ann, but James throws them out, worried that the police might discover them. As Suzy is driving home to visit her parents, her car breaks down in the pouring rain and she takes shelter in a deserted house nearby, from which she phones a garage. Seeing huge man lurching towards the house, she cowers in terror, but it turns out to be the mechanic.

Ann goes to the club where she works serving drinks with some of the other girls from the hostel. A customer tries to grope her and is thrown out by the bouncer. Later, he is garotted and impaled on some railings; his dismembered body is found by dustmen the next day.

Back at James's studio, the crew are finishing the soft porn film. One of the arc lights falls from the ceiling, killing Les, the director. As Viv, scared by all the deaths, is preparing to move out of the hostel, she sees blood dripping from the ceiling. Suzy goes to investigate and finds a tin of spilt red paint in an upstairs room. While waiting for her on the stairs, Viv is stabbed to death.

Ann goes to the film studio and talks to Philip, James's assistant, who tells her exactly what happened on the night of the party. After she leaves, Philip hears a noise and goes into the darkened studio, where the set starts to fall apart and rolls of celluloid and film cans fly at him. Falling down some stairs, he is guillotined by a shard of glass in a door frame.

When Ann returns to the hostel, she finds the police questioning Suzy and runs away. A policeman pursues her but is crushed to death by the police car, which appears to drive by itself.

On her way to James's house, Ann shelters in a parked car when a gale begins. The car begins to rock and then flies up into the trees. Petrified, she climbs out and the car falls to the ground.

Ann breaks into James's house, where she witnesses objects flying around the room and takes an axe from the wall to defend herself. James creeps out to investigate the noise and she fells him with the axe. The witch appears and the sword flies off the wall, impaling Ann to the wooden fireplace.