Michael Rogers is a wistful, aimless young photographer who works as a chauffeur and lives with his mother in London. Coming from a working-class background, he dreams of a life of luxury and is deeply fascinated by the fine arts. While driving clients around, he discovers a remote spit of land on the Devon coast called Gypsy's Acre, where a dilapidated Victorian mansion stands in a weathered landscape. He convinces himself that one day he will build a home there, designed by the famed Italian architect Santonix, whom he first met through a client.
During his time documenting Gypsy's Acre, Ellie Thomsen, a young American visiting England, is drawn to Michael's fantastical outlook. As they explore the property, they encounter Miss Townsend, an enigmatic old woman who warns that Gypsy's Acre is for sale but cursed. Ellie leaves England to continue her travels through Switzerland and Italy with Greta, her German-language tutor who has taken on the role of a personal assistant. In Ellie’s absence, Michael learns a startling truth: she is among the richest young women in the world. When Ellie returns, she explains that she did not tell him about her wealth because she worried it might discourage him. She also reveals that, while in Italy, she arranged a meeting with Santonix about her dream home and that she has purchased Gypsy's Acre.
Though Michael is initially angered by the deception, he eventually forgives her, and the couple marry in Wales. Ellie tries to keep the marriage secret, fearing her stepmother, Cora, and other family members might try to bribe Michael to dissolve the union because of the class divide. The marriage becomes international news, and their choices to build a life together draw scrutiny from Ellie's powerful circle. The family’s attorney, whom Ellie affectionately calls “Uncle” Andrew, quickly attempts to buy Michael out of the arrangement, but Michael declines, insisting he and Ellie are in love. The newlyweds purchase a local antique shop to run as their venture.
As construction begins on the dream home, Greta arrives and reveals she has taken a secretarial job in London, gradually insinuating herself into the couple’s life. Ellie is uneasy but welcomes this arrangement, while Michael remains wary of Greta and the broader family dynamic. Meanwhile, Ellie becomes unsettled by Miss Townsend, who seems to watch the house from the fields below for hours at a time. When Ellie goes missing during a horseback ride, her body is later found in the woods on Gypsy's Acre. An autopsy attributes the death to an unexpected cardiac event, but Michael refuses to accept this, raising the possibility of foul play. The search for Miss Townsend yields no results, and after the inquest, Andrew informs Michael that Ellie has named him the sole beneficiary of her estate and urges him to travel to the United States to handle Ellie's business affairs. Santonix dies after a lengthy battle with cancer, adding to the sense of upheaval.
Upon returning to Gypsy's Acre from the United States, Michael experiences a vision of Ellie as he approaches the house. He and Greta then share a renewed intimacy, revealing that they had been lovers with a shared plan to secure Ellie's estate. Greta is implicated in Ellie's death: she allegedly poisoned Ellie by lacing her allergy medicine with cyanide and bee venom, causing a fatal heart attack. The couple’s lavish dream dissolves when an envelope postmarked from New York City—sent by Andrew—arrives with dated photographs proving they had been together long before Michael met Ellie, exposing their conspiracy. Michael responds with violent rage and murders Greta by drowning her in the swimming pool. The act triggers a memory from his childhood of pushing a schoolmate into a frozen pond and taking his watch as a keepsake.
Back at the police station, Michael is interviewed by officers and Dr. Philpott, a local psychologist, and he admits to helping murder Ellie. Philpott questions the existence of Miss Townsend, suspecting she may have been used to frighten Ellie and then killed to prevent her from revealing the plot, but Michael insists Miss Townsend never existed. As the interrogation continues, Michael descends into a nervous breakdown, haunted by the memories and images connected to the people he has killed and the events surrounding Gypsy's Acre.
