Oliver Quick looks directly at the camera and states that he “loved” Felix Catton but insists that he was not “in love” with him.  

In 2006, a younger Oliver, then a first-year student at the University of Oxford, struggles socially. His only friend, at first, is a socially awkward mathematics student named Michael Gavey. Oliver strikes up a surprising friendship, however, with Felix, a popular and handsome student, after Oliver lends him his bike. Felix invites Oliver into his wealthy social circle, though Felix’s cousin, Farleigh Start, who was raised in the United States, views Oliver with suspicion. Oliver tells Felix about his difficult childhood, explaining that his parents struggled with mental health issues and drug addiction. As Felix incorporates Oliver into his social circle, Oliver abandons Michael, who warns him that Felix will grow “bored” of him eventually. As Michael predicted, Felix begins to grow distant. However, at the end of the semester, Oliver informs Felix that his father has died in an accident while drunk. Aware of Oliver’s grief and his difficult home life, Felix invites him to spend the summer of 2007 at Saltburn, his family’s English country house.  

At Saltburn, an impressive and historic estate, Oliver receives a frosty welcome from Duncan, the butler, but is received warmly, though with condescension, by Felix’s family. He meets Felix’s mother, Lady Elspeth, who is hosting her friend, Pamela, who has been having a difficult time getting “back on her feet” after a breakup with a Russian oligarch. He also meets Felix’s father, Sir James Catton, and his sister, Venetia, who struggles with an eating disorder. Farleigh, who is also spending the summer at Saltburn, resents his financial dependence upon the Cattons and Oliver’s presence at the family home. On his first evening at Saltburn, Felix sees Venetia outside on the lawn and joins her. She tells Oliver that Felix likes him because he’s “real” and notes that Felix brought a friend to Saltburn last year too. In the days that follow, Oliver, Felix, Venetia, and Farleigh enjoy the comforts and luxuries of Saltburn, drinking, playing tennis, watching movies, and reading Harry Potter and the Deathly Hallows. One evening, Oliver watches as Felix masturbates in the bathtub of their shared bathroom. After Felix exits the bath, Oliver drinks from the remaining bathwater as it circles down the drain. Shortly after, Oliver learns from Lady Elspeth that Pamela has been quietly pushed to leave Saltburn “without making a scene.” That night, Oliver looks outside his window and sees Venetia sitting out on the lawn. He goes down to join her and performs oral sex on her even though she is on her period.  

The next day, Felix seems tense over breakfast as Lady Elspeth and Sir James plan a Midsummer Night’s Dream-themed costume party for Oliver’s birthday. Oliver learns that Farleigh, who witnessed Oliver and Venetia on the lawn, informed Felix. Annoyed, Felix tells Oliver that it was “bad form” to have sex with his sister. Oliver, however, claims that he only went out to check if Venetia was okay and rebuffed her attempt to kiss him. Convinced by Oliver’s account, Felix dismisses his sister as embarrassing and characterizes Farleigh as a troublemaker. Felix discloses to Oliver that, in the past, he brought a close friend named Eddie to Saltburn, but things became “awkward” after Eddie had a fling with Venetia, putting an end to their friendship. That night, Venetia waits outside for Oliver, but he ignores her. The next day, Farleigh angrily accuses the Cattons of spending lavish amounts of money on the planned party for Oliver while his own mother, who was cut off financially by her brother, Sir James, struggles financially. In the argument that ensues, Felix defends his father’s choice to cut off Farleigh’s mother, and Farleigh, who is biracial, implies that the Cattons are racist.  

That night, the Cattons host a large dinner party and Venetia angrily dismisses Oliver as one of Felix’s “toys.” That night, while the Cattons and their guests sing karaoke at Saltburn, Oliver and Farleigh have a hostile but flirtatious conversation, and Farleigh admits that he tried to drive a wedge between Felix and Oliver. Farleigh then pressures Oliver to sing karaoke, selecting a song that insultingly suggests that Oliver is using Felix for money. That night, Oliver enters Farleigh’s bedroom and threatens Farleigh while also initiating sex with him. The next morning, Farleigh is suddenly evicted from Saltburn when Sir James learns of an attempt by Farleigh to sell valuables pottery stolen from the house. Sir James and Lady Elspeth ignore the topic, and Lady Elspeth casually notes that Pamela has died.  

Felix surprises Oliver with a “road trip” but Oliver panics when he realizes that Felix is taking him to visit his mother. At Oliver’s home, Felix learns that Oliver has deceived him about his own background. Oliver has multiple siblings, his father is alive, and his parents are middle class, living in a respectable suburb. Stung by the revelation of Oliver’s deceit but hoping to spare his family any embarrassment, Felix decides not to disclose the truth to the other members of the Catton family. Nevertheless, he demands that Oliver leave Saltburn after his birthday party. The party is an extravagant affair. Oliver sees Farleigh, who gloats about his return to the family, and attempts to rekindle his friendship with Felix, but Felix pushes him away and tells Oliver that he needs help. The following morning, Felix’s body is found in the hedge maze at Saltburn. Over a tense breakfast, Oliver implies that Farleigh gave drugs to Felix and is therefore responsible for his death, and Sir James kicks Farleigh out of the house for good. Mourning Felix, Oliver lies over his grave, naked, and masturbates into the soil. After the funeral, Felix stays at Saltburn at the request of Lady Elspeth, who is comforted by his presence. Venetia, however, becomes increasingly upset and, after rejecting Oliver’s attempt at seduction, commits suicide in a bathtub by slitting her wrists with razors. Distrustful of Oliver and wary of his wife’s close relationship to him, James bribes Oliver to leave Saltburn without making a scene.  

In 2022, years later, Oliver encounters Lady Elspeth in a cafe after reading about the death of Sir James. She invites him to return to Saltburn, and the two spend time together as Lady Elspeth falls terminally ill. As she nears death, lying unconscious in bed, Oliver confesses his guilt for various events, including deaths, at Saltburn. He punctured Felix’s bike tire at Oxford in order to orchestrate their first encounter and, during his birthday party at Saltburn, killed Felix by poisoning his drink. He framed Farleigh for theft of valuable pottery and left razor blades on the bathtub for Venetia when she was in a disturbed state, prompting her to commit suicide. He also arranged his meeting with Lady Elspeth at the cafe, hoping to get close to her and inherit her assets, including Saltburn. After making his confession, he kills Lady Elspeth by removing her life support, inheriting the family fortune and home. Celebrating the success of his plan, Oliver snorts a line of cocaine and dances naked through Saltburn as its new owner.