David Linton, a would-be author with an alcohol problem who is also involved in passing counterfeit notes, and his wife Jean Linton drift from one rented flat to another, each leaving unpaid bills behind. He has had several affairs during their marriage, and their luck seems to change when Jean inherits a house and £1000 from a distant aunt.
They visit the country house named “Four Winds” and decide to move in, only to be told by the housekeeper, Mrs. O'Brien, that the home is already inhabited by a poltergeist she has named "Patrick" after her late husband. Patrick makes his presence felt by moving furniture, breaking mirrors, and other unsettling phenomena, which Jean witnesses firsthand. David mistreats Jean, while Patrick begins to warn him to stop.
David spends more time at the local pub, “The Plough,” where he learns about Valerie Stockley, a provocative typist who could help him with his manuscript. The estate agent Morris Lumley offers him £6,000 for the house and land, but the property is still in Jean's name, and he cannot force a sale. To further his plans, he hires her, who calls herself “Mrs.” but whose marriage status is unclear, as a typist, and their affair begins in earnest.
David steals money from Jean to fund Valerie’s expenses, and Valerie suggests that once her divorce comes through, she will marry him. But she learns that Jean controls the property and money, and she taunts him with the idea that he should eliminate Jean to inherit. The poltergeist Patrick, protective of Jean, even helps her uncover David’s affair; but after a confrontation, David convinces Jean the affair is over and he wants another chance.
David’s plan to harm Jean escalates: he attempts to push her down the open lift shaft in the house, but Patrick blocks the move by closing the safety gate. He then dissolves sleeping-pill in her cup of hot milk; Patrick triggers a loud alarm each time she raises it to her lips, alerting her to danger. David returns later to check if she is dead.
Jean consults a solicitor in London about a divorce, but the lawyer dismisses the poltergeist defense as insufficient in court. Jean learns that her case is not straightforward; the poltergeist cannot be used as a courtroom defense to prevent murder.
With Jean away in London, David continues his relationship with Valerie, and Patrick punishes them by locking them in the bedroom and setting Four Winds aflame. When Jean returns, she discovers that both David and Valerie have perished in the blaze, trapped behind the bedroom’s barred windows.
