Plot
Alistair and Miles, both with aristocratic connections, start their first year at Oxford University. Miles is friendly and level-headed, cordially offering to switch rooms when Alistair's assigned room does not meet with his parents' approval, and beginning a relationship with Lauren, who has a working-class, Northern background. Alistair is an insecure, arrogant, and cold-hearted snob. The two are tutorial partners at Oxford, where Alistair is blatant in his contempt for Miles and his left-leaning politics.
The Riot Club, a long-established exclusive drinking club priding itself on hedonism and the belief that money can buy anything, is on the hunt for new members to maintain its roster of ten men, all of whom must be educated at private schools. Alistair is invited by Harry, whom he has met during the start of their term. Miles, who was out drinking in the pub, is invited by Hugo, another Riot Club member. Alistair finds a new friend in Harry, who introduces him to his Uncle Jeremy (Tom Hollander), a senior MP—which Alistair himself aspires to be one day. After an unpleasant initiation, Miles and Alistair become members of the Riot Club.
Having been barred from most establishments in Oxford, the club has its annual dinner at the function room in a country pub. Alistair and Miles are both surprised to see each other there, Alistair showing open disdain. The Club begins their dinner, and though the landlord is initially excited to have a wealthy, aristocratic party dining at his establishment, their raucous behaviour annoys the pub's other patrons, some of whom leave. Chris, the landlord, is put off by their behaviour and tells them that they are disrupting his business; the boys settle with an arrangement with them paying for his losses to let them continue to stay, which he reluctantly accepts. After the escort Harry hired refuses to perform group oral sex, Alistair takes Miles's phone and texts Lauren without Miles knowing. Lauren then shows up at the pub to the surprise of Miles, whom the boys promptly proposition to do what the escort would not. They insult her, and Lauren then attempts to leave the pub but is assaulted by one of the members. Miles struggles to rescue her as the other members hold him back. Hugo intervenes and orders the boys to let her leave, which she does.
Miles, drunk and seemingly depressed after what happened to Lauren, stays quiet for the rest of the night, while Alistair works up the rest with his political ideals of the rich and the poor. Becoming progressively more drunk and ingesting drugs, they start to wreck the room. When Chris comes to confront them, Alistair insults Chris by giving him money which he does not accept, telling them they are no better than a bunch of kids breaking shop windows and that they are just spoiled brats. Alistair punches him followed by the others who viciously attack him until he becomes unconscious. While the members become frantic realizing what they just have done, Miles calls for an ambulance.
The boys are all arrested but believing that the club is more important than the individual, they agree not to give statements. The club meets after the incident and agrees that Miles, as the newest club member, should take the blame for the attack on Chris. Miles tries to apologise to Lauren, who tells him to never talk to her again. Later, Chris's skin is then found underneath Alistair's fingernails, meaning they can arrest and charge him. Alistair is sent down (expelled) from Oxford, being the only one arrested for the incident, whilst the others are allowed to continue their studies without any criminal charges. After a talk with the dean, Miles is approached by the new president of the Riot Club, Guy Bellingfield, to re-join next year, but after nearly having to leave university because of the scandal, he decides to leave the club, a decision which the new president mocks.
Alistair is invited to a meeting with Jeremy in London, who asks for the Riot Club to be kept out of future court appearances, and assures Alistair that despite being kicked out of Oxford, the boy is still a Riot member. Though Alistair is initially aggressively dismissive of Jeremy's proposed assistance, Alistair is brought around when Jeremy offers the boy a position in his office and an assured future. The film concludes with Alistair leaving the meeting with Jeremy, a smug smile on his face as he walks down the street.
