Charlotte Castang, Charlotte Gainsbourg, is a 13-year-old girl from a working-class background who lives near a nightclub called the Roule-Roule with her widowed father, her crass brother Jacky, and their devoted maid Léone Bernadette Lafont. Her only friend is Lulu, a sick 10-year-old whose mom works late shifts at a hospital, and who she initially regards as a pest. At school, during a swimming lesson, she struggles to dive and crashes her knee. After a nurse checks her, she slips into a classroom amphitheatre to watch a tape of a rehearsal by Clara Bauman, a pianist prodigy her age, and a teacher allows her to stay on the last day of term. Watching Clara perform, Charlotte grows fascinated by her poise and sophistication, secretly longing to be part of that world and to call Clara a friend.
The following day, Charlotte and Lulu wander through antiques shops, and a car stops by with Clara in the passenger seat. Charlotte guides them to a metalworker who is repairing Clara’s piano stool, and Clara asks for the stool to be delivered the next day for a show at a rented lake house. After Clara thanks Charlotte with a kiss on both cheeks, Charlotte rushes home to tell Leóne about the encounter. At home, she clashes with Jacky, who pees in the bushes, and she lashes out at Lulu before Leóne scolds her for rude behavior. She drifts to sleep beside her father, who chastises her gently before letting her lie there. The next morning, Jacky heads off on vacation, and Charlotte half-hopes he’ll take her with him.
Charlotte, waiting outside a metalworking shop, observes the delivery of Clara’s piano stool. A driver stops near her house, and she pretends to be 15 while naming herself as a sister to Jean, the man who accompanies the stool. When he drops her off near home, he leans in and kisses her on the lips. They journey to the lake house where Clara is staying, with Charlotte carrying the stool under the pretense of helping Jean. She decides to stay, driven by a desire to meet Clara, and eventually slips away to the pool area where Sam Jean-Claude Brialy—Clara’s concert manager—appears. Clara is away practicing, but she tells Charlotte to stay for a party that evening. Although Charlotte is hungry, she forgoes food, and Sam tries to coax her to swim, a moment that leaves her dizzy. When Clara returns, she lends Charlotte one of her concert dresses and jokes that Charlotte could be her manager one day. Charlotte watches Clara perform at the party before returning home, filled with a new sense of possibility.
Chartered by longing, Charlotte calls Sam repeatedly, clamoring that she will leave with Clara in July, though her calls go unanswered. She reconnects with Jean at a hotel bar and reluctantly agrees to go see The Exorcist with him later, while promising to share the film outing with him. Back home, Charlotte shares a picnic with Lulu and Leóne, but the day ends in a fraught argument that leaves her in tears until Leóne helps calm her down. Later, she and Jean finish the movie, and he leads her to his room, locking the door behind them. He shows her an illuminated globe that spins, and when she asks to leave, he hugs her and attempts to kiss her. She frees herself and, in a moment of desperate resistance, strikes him with the globe, breaking it.
Returning to Clara’s orbit, Charlotte goes to Clara’s concert with Lulu and Leóne. She hopes to leave with Clara, but Sam tells her to wait after the show, presenting a letter Clara wrote for her. Though Lulu is excited for Charlotte, she ends up bleeding from the nose and fainting as they head out.
In the end, a quiet scene unfolds in a children’s hospital: Charlotte gives Lulu a perfume she uses herself, and the two hold hands as they look out from a balcony and talk, a small moment that hints at care and connection amid the intense, complicated year they have shared.
