At dawn one fateful morning, Clarisse embarks on an emotional journey, meticulously dressing and gathering her belongings while ensuring that her husband, Marc, and their two children, Paul and Lucie, remain unaware of her departure. The sound of Lucie, an aspiring pianist, pretending to be asleep underscores the tension in the air as Clarisse makes her way to a gas station. There, she encounters a friend whose help in repairing her car unveils a vague reference to a troubling incident from two months earlier, as she expresses her intention to head to the sea.
The following day, life continues unchanged for Marc, Paul, and Lucie, who are blissfully ignorant of Clarisse's absence. Meanwhile, as Clarisse drives towards her destination, her mind plays out imagined conversations with her loved ones, who seem to respond to her thoughts as they navigate their daily lives. Upon reaching the beach, she indulges in a turbulent night of drinking at a local bar and ponders how Marc will eventually explain her absence to the kids. As the months roll on, the emotional distance grows between Marc and the children, compounded by the stark reality of Clarisse's departure becoming increasingly evident. Occasionally, Clarisse's narration overlays their lives, and in an uncanny twist, the family appears to be reacting to her voice.
As Clarisse adapts to her new life, taking on jobs such as a tour guide for German tourists, she struggles with her emotions and lashes out at a guest who admonishes a child. The narrative takes a poignant turn as a flashback reveals tragic details: Marc, Lucie, and Paul died in a devastating skiing accident, buried by an avalanche. The life scenes previously depicted were merely Clarisse's coping mechanisms, as she held onto the illusion that it was she who had left them behind. The haunting reality sets in—she had been at work, intending to join her family the following day, but instead faces overwhelming survivor's guilt, with police unable to recover their bodies from the treacherous snow.
As Clarisse reflects on her memories, she recalls meeting Marc at a club, and that the very car she drives now is the one he had taken her home in. One day, she spots a choir group practicing and is drawn to a girl who bears a striking resemblance to Lucie. Deeply moved, Clarisse observes the girl boarding a bus, reminiscing about her daughter. Subsequently, she crosses paths with a flutist at a lounge, where their shared interest in a documentary about Martha Argerich leads to a brief, intimate moment that she abruptly ends by resting her hand on his chest, feeling his heartbeat.
Her imagination continues to weave parts of her reality, crafting visions of Marc raising Paul and Lucie in her absence, with Lucie evolving into a composite of the choir pianist and the renowned Martha Argerich. A teacher encourages her to audition for the prestigious Conservatoire de Paris. In a bittersweet return during the transitional spring at the ski resort, Clarisse dines alone at a table set for four, only to be startled by a barking German Shepherd outside.
As Lucie travels to Paris to audition, Clarisse enters the judging room, inadvertently causing Lucie to flee in distress. Clarisse, trying to comfort her, discovers that the “Lucie” auditioning is actually the pianist, whose real audition she has interrupted. The girl's parents confront Clarisse, claiming that she has been stalking them, threatening to call the police if she doesn’t leave. Overwhelmed, Clarisse almost whispers, “I have to do it all alone,” as she walks away in despair.
The scene transitions back to the ski resort, but this time, the barking dog heralds the return of search and rescue teams—carrying the lifeless bodies of Marc, Lucie, and Paul. Overcome with grief, Clarisse screams and tries to lash out at the bags containing what remains of her family. Upon finally returning home, she encounters a real estate agent, who aids her in assessing the property. With a heavy heart, she compiles all the photographs of her family, wrapping them in Lucie's sheet music. In a symbolic act of moving forward, she drives away, while the sounds of music and driving resonate over the credits, encapsulating her turbulent journey.
