TERROR

Three hundred years ago, the witch Mad Dolly is captured on the orders of Lord Garrick. She is about to be burned at the stake when she invokes the Devil, causing one of her executioners to catch fire. Garrick rushes back to his house, where a disembodied arm bursts through a wall and strangles him. Lady Garrick is confronted by a sword-wielding Mad Dolly, who beheads her and curses the family's descendants.

Credits roll, revealing that these scenes form the ending of a horror film directed by James Garrick – the last of the Garrick line with his cousin Ann, an aspiring actress. James is hosting a preview screening for Ann and their friends at the largely unchanged Garrick house, which he now owns. He believes his film to be based on true events and has also inherited Mad Dolly's sword.

Gary, a mesmerist, hypnotises Ann as a party trick. In her trance, Ann picks up the sword and swings it at James, wounding him slightly. After being overpowered by the other guests, she comes to her senses and leaves the house. When Carol departs, she is stabbed to death in the surrounding woods by an unseen assailant. Ann returns to her hostel in London with bloodstained hands, watched by her roommate Suzy.

When her car breaks down on a country road at night, Suzy makes her way to a nearby house to seek help. Finding no one at home, she telephones a garage to request a tow truck. While waiting to be picked up, she has several near misses with a tall, shadowy figure who appears to be stalking her, leaving her terrified. However, this is revealed to be the garage mechanic.

More murders and strange deaths follow. At the strip club where Ann and her friends work as waitresses, a patron is ejected by a bouncer after groping Ann; on returning home, he is thrown onto a row of spiked railings and dismembered. At James's film studio, an overhead lamp falls to the floor and crushes Les, a short-tempered director trying to shoot a sex film called Bathtime with Brenda. Viv – the title character, and one of Ann's friends – is stabbed to death at the hostel. Ann visits James's assistant Philip at the studio and tells him that she has no memory of her attack on James or how she got home the night Carol was murdered. After she leaves, props and equipment start flying around the studio and pelting Philip, who is then decapitated by a falling sheet of glass.

Ann flees the hostel when she comes across Suzy being questioned by police about her and Viv. An officer pursues her but is repeatedly run over and crushed by his car, which is being driven by a supernatural force. While making her way to the Garrick house, Ann is caught in unusually strong winds and takes refuge in a parked car; she is forced to jump out when the vehicle inexplicably rises into the air. Reaching the house, she experiences bizarre visions and sees various objects moving of their own accord. She is startled by the sudden arrival of an unseen figure and strikes him down with an axe, only to find she has killed James. The spirit of Mad Dolly re-appears, cackling, as her sword flies across the room and fatally impales Ann against a wall.

Ann, tormented by supernatural events and bizarre visions, flees to the Garrick house where she is confronted by inexplicable phenomena. In the chaos, she strikes down an unseen figure with an axe, only to discover she has killed James.

The film ends with Ann accidentally killing James, her cousin and the last of the Garrick line, after being driven to desperation by the relentless supernatural curse. This conclusion underscores the inescapable grip of Mad Dolly’s vengeance and the blurred boundaries between reality and madness, as Ann is manipulated by forces beyond her control.