Chris Washington, a talented Black photographer living in Brooklyn, prepares for a weekend trip to upstate New York to meet the parents of his white girlfriend, Rose Armitage. Chris asks if her family knows he is Black; Rose dismisses his concerns, reassuring him her parents are welcoming liberals. During the drive, their car strikes a deer. When a local white police officer demands Chris's identification despite him not driving, Rose aggressively steps in to defend him, which Chris sees as a sign of solidarity.

At the Armitage estate, neurosurgeon Dean and hypnotherapist Missy welcome Chris warmly, though Dean makes awkward, performative efforts to connect. Chris notices the family's Black domestic workers—housekeeper Georgina and groundskeeper Walter—behaving in an unsettlingly stiff, robotic manner. That night, unable to sleep due to cravings to smoke, Chris walks outside, witnessing Walter sprint at full speed toward the house before turning abruptly, and Georgina staring blankly into a dark windowpane.

Returning indoors, Chris is invited into Missy's study. She questions him about his mother's childhood hit-and-run death while rhythmically stirring a silver spoon inside a tea cup. The auditory hypnosis induces total paralysis, plunging Chris's consciousness into the "Sunken Place"—a pitch-black cosmic void where he floats helplessly, watching his body from a distant cinema screen. Chris wakes in bed the following morning believing it was a nightmare, only to discover his cigarette addiction is completely gone.

The next day, dozens of wealthy white guests arrive for the Armitages' annual garden party. The visitors express invasive, fetishistic interest in Chris's physique, genetic traits, and photography. Chris encounters Logan King, another Black guest who dresses in vintage clothes and acts with eerie subservience beside a much older white woman. When Chris attempts to discreetly snap a photo of Logan on his phone, the camera flash triggers a violent reaction: Logan's nose bleeds, and he frantically grabs Chris, screaming: "Get out!"

Dean explains Logan suffered an epileptic fit. Disturbed, Chris sends Logan's photograph to his TSA friend Rod Williams in New York, who identifies Logan as Andre Hayworth, a Brooklyn acquaintance who vanished months earlier. While guests hold a silent, coded outdoor bingo auction—bidding on Chris himself, won by blind art dealer Jim Hudson—Chris packs his bags. In a bedroom closet, he discovers a hidden box filled with photographs showing Rose in romantic relationships with numerous past Black partners, including Walter and Georgina.

Realizing the entire trip is a calculated trap, Chris tries to leave. The Armitage family corners him in the foyer: Dean blocks the exit, brother Jeremy wields a lacrosse stick, and Rose cold-heartedly dangles the car keys, smiling as she refuses to hand them over. Missy strikes the silver spoon against her teacup, instantly sending Chris crashing into the Sunken Place.

Chris awakens strapped to a leather armchair in the basement, where a retro instructional television explains the Armitages' "Coagula procedure"—a proprietary neurosurgical operation pioneered by grandfather Roman Armitage. A white elder's brain tissue is transplanted into the donor's skull, retaining the donor's physical motor skills while suppressing their consciousness inside the Sunken Place. Jim Hudson appears via video link, explaining he bought Chris to hijack his artistic photographic eye.

Chris plugs his ears with cotton ripped from the leather armchair stuffing, blocking out the chime of Missy's spoon on the TV speakers. When Jeremy unlocks the restraints for surgery, Chris feigns unconsciousness before driving a ceramic cup into Jeremy's skull. Arming himself, Chris impales Dean with the mounted antlers of a buck head and kills Missy by jamming a letter opener into her neck.

Chris steals Jeremy's car and drives away, accidentally striking Georgina on the driveway. Overcome with guilt remembering how he failed to act when his own mother died, Chris pulls Georgina into the car. However, Georgina—possessed by grandmother Marianne Armitage—attacks him, causing the vehicle to crash into a tree, killing her.

Rose and Walter (possessed by grandfather Roman) pursue Chris on foot with a rifle. Chris flashes his phone camera at Walter, temporarily breaking the mental hypnosis. Acknowledging his restored self, Walter takes the rifle from Rose, shoots her in the stomach, and turns the weapon on himself, committing suicide.

Chris strangles Rose on the road, but stops himself from taking her life. As Rose bleeds, flashing police cruiser lights illuminate the road. Rose feigns victimhood, screaming for help. The driver door opens to reveal not a local police officer, but Chris's best friend Rod Williams in his airport TSA vehicle. Rod unlocks the passenger door, telling Chris: "I mean, I told you not to go in that house." Chris climbs inside, leaving a dying Rose lying on the asphalt as they drive away to safety.