The film centers on Helen, a reclusive translator who invites her friend Anne to spend a weekend at her family's estate, a secluded manor by a lake tucked away in a forest. The setting feels timeless and slightly uncanny: stone walls cloaked in ivy, rooms that seem half-forgotten, and the water outside that mirrors the tension gathering between the two women. The two have grown distant after Helen’s return to England and a recent breakup with her boyfriend, and their reunion unfolds with careful, uneasy conversations about life, memory, and what might lie beyond death. The mood is contemplative at first, but the house gradually reveals a more suffocating undercurrent as the storm outside intensifies.
The next morning, Helen stops by a local chemist’s shop, where the clerk—Burke—asks about her friend, Cora Porter, whom he has heard spoken of in hushed whispers. Returning to the manor, Helen and Anne wander the grounds and woods, and Helen reveals a rumor of a drowning at the lake, a past tragedy that seems to hover over the property. Their walk leads them to the water again, where the atmosphere grows increasingly unsettled. When they cross paths with Brady, the handyman who lives in the stables, Anne notes that he has been watching Helen with an unsettling intensity, a detail Helen herself dismisses with a mixture of derision and fear. Later, Helen begins to spy on Brady from the house, her nerves frayed by the isolation and the storm.
Sleep becomes elusive for Helen; she hears voices and sounds emanating from the attic, and the house seems to press in from every side. The following morning, Anne borrows Helen’s car and heads into town. On the way back, she stops by the lake, lights a cigarette, and encounters Brady again. He introduces himself more plainly, mentions Cora, and hints at things he’s seen in relation to the house and its occupants. Anne returns to the manor and finds Helen in a state of distress, confessing to illness and, at one point, a dangerous kiss that troubles them both. The tension between the two women deepens, complicated by the presence of the men around them and the sense that someone else may be in the house with them.
That night, the house is filled with moans and whispers. Anne is awakened and asks if anyone else might be living there, but Helen shrugs it off. John arrives to pick up Anne, and Helen is blindsided to see John kiss Anne in the car, a moment that stings with jealousy and fear. Later, Helen’s attention is drawn to an attic door in her bedroom, and she experiences a moment of intense arousal before the atmosphere in the house turns deadly: a figure bursts into Anne’s room and stabs her to death.
Hannah, the housekeeper, arrives the next morning and finds Helen sleeping on the couch, urging her to stay hidden for a few days. At the drugstore, Hannah tells Mr. Burke and recalls a story of Cora having an encounter with Brady in the stables—and that Cora has not been seen since. While wandering the woods, Helen is confronted by Brady, who questions her about Anne’s whereabouts and insinuates that Helen may have harmed both Anne and Cora. Helen flees in panic.
Back in the house, Anne’s dead body is discovered, sitting in a chair in Helen’s bedroom, while Helen is haunted by disembodied voices and other unsettling phenomena. A rainstorm brings John back, searching for Anne, and he enters through an unlocked door. In a violent outburst, Helen kills him, stabbing him multiple times in the head and neck. Later that night, Brady pays another visit to press for answers about Cora; he reveals he has found Cora’s decomposing body in the lake and has even cut off a few strands of her hair to show Helen. Brady also intimates that he witnessed Helen push Cora into the water, a claim Helen coolly denies. In a flash of recognition framed by lightning, she seems to glimpse Cora standing in a doorway as the storm rages on.
The next morning, Hannah, Mr. Burke, and his protégé Nick arrive at the house to try to understand what happened. They discover Brady’s corpse in the living room and, while exploring upstairs, find John dead in the hallway, with Helen standing outside the confusion, staring blankly through a window. In the yard, Helen witnesses a final, unsettling sight: Brady and Cora appear to embrace, as if the past truths of the estate are finally laid bare for her to confront.
