In the 2000s, Amanda is an aimless 25-year-old Italian woman who feels alienated from her wealthy family—particularly her mother and her older sister—and struggles to form meaningful social connections after finishing school in Paris. Despite having the opportunity to work in her family's pharmacy business, she instead spends her time wandering the city, frequenting the local cinematheque and raves in search of friends, trying to forge online connections via video chat rooms while staying in a hotel room funded by her parents, and visiting an aging horse tied up at a nearby farm. At her mother's suggestion, Amanda visits Rebecca, the daughter of her mother's friend Viola and a childhood friend she has not seen for many years. A former athlete, Rebecca lives a reclusive life, rarely leaving her room and regularly attending psychotherapy sessions at home. After Rebecca slams her bedroom door on Amanda without saying a word, Amanda learns from Viola that she and Rebecca were inseparable as toddlers before Amanda's family moved away. Convinced that she and Rebecca could have been best friends all along, Amanda becomes determined to rekindle their friendship. After Amanda repeatedly tries to force her way into Rebecca's room, Rebecca finally lets Amanda in and they warm up to each other. At a rave, Amanda meets a boy whom she suspects is a drug dealer, but he clarifies he hands out free condoms at raves. The two go out to eat and become acquainted, after which Amanda saves his contact as "My Boyfriend" on her phone. When the boy invites Amanda to his upcoming birthday party, telling her she can bring someone, she invites Rebecca to accompany her. As the two girls continue to spend time together, Amanda moves in temporarily with Rebecca, though Amanda becomes jealous of Rebecca's therapist, Ann. The boy from the rave tells Amanda to stop texting him incessantly as he is dating another girl, leaving her heartbroken. Back at Rebecca's house, Ann instructs Amanda to tell Rebecca that she is leaving for Paris, before declaring that Amanda's borderline personality traits are not good for Rebecca. In despair, Amanda flees, steals the horse and returns to Rebecca's house with the horse, leaving it in the garden. She then goes to Rebecca's room and tries to persuade her to run away with her, but Rebecca agrees with Ann's assessment and reveals that Viola made Rebecca befriend Amanda when they were children because everyone felt sorry for Amanda. Devastated, Amanda leaves. Amanda moves back into her family's villa, and her relationship with her mother and sister gradually improves. Viola approaches Amanda, asking her to reunite with Rebecca. Amanda tells Viola that Rebecca can find her at the local cinematheque, but Rebecca never shows up. Later, the boy from the rave accuses Amanda of crashing his party the previous night and setting off firecrackers in his living room, but she denies it. Realizing that this was Rebecca's doing, Amanda goes to her house and thanks her. Rebecca confesses that she rode to the party on horseback, but the firecrackers scared off the horse. Amanda and Rebecca set off in search of the horse, suggesting a tentative reconciliation.

On November 30, 1962, a month after the Cuban Missile Crisis, George Falconer is a middle-aged English college professor living in Los Angeles. George dreams that he encounters the body of his longtime partner, Jim, at the scene of the car accident that took Jim's life eight months earlier. He bends down to kiss his dead lover. After awakening, George delivers a voiceover discussing the pain and depression he has endured since Jim's death and his intention to end his life that evening. George receives a phone call from his dearest friend, Charley, who projects lightheartedness despite also being miserable. George goes about his day putting his affairs in order and focusing on the beauty of isolated events, believing he is seeing things for the last time. At times, he recalls his sixteen-year-long relationship with Jim. During the school day, George comes into contact with a student, Kenny Potter, who shows interest in George and disregards conventional boundaries of student–professor discussion. George also forms an unexpected connection with a Spanish male prostitute, Carlos. That evening, George meets Charley for dinner. Though they initially reminisce and amuse themselves by dancing, Charley's desire for a deeper relationship with George and her failure to understand his relationship with Jim angers George. George goes to a bar and discovers that Kenny has followed him. They get a round of drinks, go skinny dipping, and then return to George's house and continue drinking. George passes out and wakes up in bed with Kenny asleep in another room. While watching Kenny, George discovers that he has fallen asleep holding George's gun to keep George from killing himself. George locks the gun away, burns his suicide notes and in a voiceover explains that he has rediscovered the ability "to feel, rather than think". As he makes peace with his grief, George suffers a heart attack and dies, while envisioning Jim appearing and kissing him.