A young film student in the early '80s becomes romantically involved with a complicated and untrustworthy man.
Julie (Honor Swinton Byrne) is a young film student living in London. She comes from a privileged background and wants to make a film about a young boy and his mother in a much poorer part of the city, though has trouble articulating exactly what it's going to be to her professors. She spends her days going to class and attending parties with her film school friends. When her roommate moves out, she has a nice apartment all to herself.
She meets Anthony (Tom Burke), an older man who works in the government, and the two have tea. Anthony has to leave town for work, but when he returns he asks if he can stay with Julie. She agrees, and quickly, the two are spending all their time together. Eventually, they sleep together - Julie notices bruises on his arm, but he insists it's nothing.
The two continue seeing each other, with Julie focusing less and less on school and her friends. The two meet each other's families - Anthony's from a more working class background, and Julie's parents Rosalind (Tilda Swinton) and William (James Spencer Ashworth) from a more posh background, with William and Anthony getting into a spirited political debate. As Anthony and Julie continue to date and live together, Anthony is constantly asking Julie to borrow money, which she never questions - she in turn keeps asking Rosalind to borrow money, saying it's for film equipment for school.
The couple has two of Anthony's friends over for dinner, including the pretentious Patrick (Richard Ayodade). He questions Julie about what she and Anthony really have in common, and when Julie is confused, he casually explains because Richard is a habitual heroin user and Julie doesn't seem to do drugs at all. Julie is shocked and horrified but continues living with Anthony, still in love with him. At one point she returns home from school to find their apartment robbed, and is devastated to have lost so many of her most precious things.
Richard decides to take Julie to Italy, who is thrilled as she has never been - but the dawning realities of her relationship keep hitting her. Once home, she confronts Anthony about stealing from her, feeling extremely violated and distrustful. But in the manner he always does, Anthony spins the conversation back to her and she ends up apologizing for not understanding him. She still remains suspicious and questions him when he goes out on whether he scored, and even follows him sometimes - but he always denies. He continues borrowing money from her and she continues giving it.
One evening, Anthony does not come home, and Julie finds out he's been arrested. In the apartment she discovers heroin and needles. When he returns, she angrily kicks him out. Freed of Anthony, she dives back into her film school work, and her friends who have noticed her being distant for so long are happy to have her seemingly present again. She begins dating other people. At one point, Anthony's mother calls to ask if she has seen him, but she tells her she hasn't. Eventually, she gets a letter from Anthony, and agrees to meet him for another tea. The two easily slide back into their familiar chemistry, and he moves back in and the two resume dating.
It's mostly good between them, but at one point Julie catches Anthony in the middle of a violent fit and cowers, trembling. Meanwhile, Rosalind has decided to return to school herself, and is staying at Julie's place for a spell. One night, Anthony doesn't return home - Julie leaves a note for him outside of the apartment telling him not to worry about waking them and that he can buzz anytime. The next morning, the phone rings, and Rosalind takes the call. She tells Julie that Anthony overdosed on heroin and was taken to the hospital but has died. Julie is in shock and adrift. She returns to film school and goes back to work on her film, no longer the innocent young girl she once was. She looks outside, directly into the camera, stoic and hardened.