While vacationing in
Italy, American couple Louise and Ben Dalton (who live in
London) and their preteen daughter Agnes meet and befriend free-spirited British couple Paddy and Ciara and their son Ant, who's unable to communicate verbally. Once home, Louise and Ben are at odds over his unemployment and her infidelity of sexting with another man from Agnes's school. A letter from Paddy and Ciara arrives, inviting the Daltons to their remote farmhouse in
Devon. The family decides to go, hoping the change of scenery will be good for them and for Agnes, who has
anxiety and is
attached to a stuffed rabbit named Hoppy. Arriving at the farmhouse, Louise, Ben, and Agnes are warmly welcomed, but as they spend more time at the house, they begin to grow unnerved by strange incidents and
passive-aggressive behavior from their hosts that cross boundaries. Louise is also troubled by Paddy and Ciara's aggressive treatment of Ant, who they learn was born with a genetic condition that manifested as a
smaller tongue and
aphasia, leaving him unable to communicate with his family. One evening, the adults go out for dinner, leaving Agnes and Ant in the care of a babysitter named Muhjid, which unnerves the Daltons. While playing
hide and seek with Muhjid, Ant shows Agnes a collection of watches Paddy has and a message written in
Danish; Agnes is unable to understand him. At dinner, Paddy challenges Louise's
vegetarianism and jokingly simulates a sex act with Ciara, shocking their guests. Upon returning, Louise later discovers Agnes has been moved to share a bed with a drunken Paddy and Ciara. Horrified, Louise flees with her family but they are forced to return by Agnes, who left Hoppy behind. Upon retrieving Hoppy, Paddy and Ciara apologize for their behavior, and subtly accuse the Daltons of judging them. The Daltons decide to stay to keep the peace, but the strange, unsettling behavior continues. After an incident where Paddy throws a chunk of cheese at Ant, Ant steals a set of keys and leads Agnes to a locked shed. Inside is a collection of luggage and personal possessions belonging to various families. Using a photo album, Ant reveals to Agnes that Paddy and Ciara are
serial killers who lure families to their farmhouse, rob and kill them, then cut out the tongues of their children, using them to assist in luring their next victims. Ant shows Agnes that this has happened to him and his loving family, and that Paddy and Ciara intend to make the Daltons their next victims. Agnes fakes
having her first period and manages to get Louise and Ben alone to explain the situation. At their wit's end, the family decides to leave, calmly so as not to arouse suspicion and contact the police to save Ant. Paddy and Ciara, realizing that their plan has been figured out, sabotage the Daltons' car and hide Agnes's bunny to delay their departure, subtly mocking them as they do so. When the Daltons finally drive off, Paddy throws Ant, who cannot swim, into a pond. Ben rescues Ant before a gun-wielding Paddy and Ciara capture them, and force them to transfer their savings before preparing to kill them and cut out Agnes's tongue. However, the Daltons immediately fight back, with Louise attacking and injuring Paddy, allowing the Daltons and Ant to flee into the house, while a stunned and enraged Paddy, Ciara, and their accomplice from the diner, Mike, hunt for them. In the ensuing chase and struggle, Louise kills Mike and saves Ben before the family flees to the roof, while Ciara attempts to shoot them with a
shotgun but Louise hits her and Ciara ultimately falls down the roof to her death. As the family attempts to escape, Paddy emerges, holding Agnes at gunpoint. As Paddy declares his intention to replace Ciara with Agnes as his companion, Agnes manages to inject Paddy with a syringe of
ketamine originally intended for her, incapacitating him. As the family departs, Ant approaches Paddy, and after he acknowledges his fate by saying to Ant, "That's my boy", an enraged Ant bludgeons him to death with a brick while screaming, letting out all his pain and anger towards him. The traumatized family and Ant leave the farmhouse; on the drive, Agnes gives her stuffed bunny to Ant, who sobs quietly. ==Cast==