Claire is a middle-aged professor specializing in French literature, navigating a complex life as she shares custody of her two sons with her ex-husband, Gilles. Amidst this, she engages in a relationship with the younger Ludovic, who views their affair as something light and casual. As time goes by, Ludovic begins to pull away from Claire. Distressed, she tries to reach him, only to have his roommate Alex answer, pretending that Ludovic is unavailable.
In an attempt to cope, Claire creates a fictitious identity, "Clara Antunès," on Facebook to engage with Alex. This leads to an emotional and intensely cybersexual relationship that gradually develops. When Alex insists on meeting her in person, Claire, now fully enveloped in her persona as Clara, claims she is moving to Brazil to get married, thus choosing to end their digital affair to avoid a real-life confrontation. Subsequently, Alex decides to delete his account, prompting Claire to seek out Ludovic for information about him. It is through Ludovic that she learns of Alex's tragic demise—he has taken his own life, heartbroken over a relationship with a "psychopath" from Facebook.
These intricate story elements unfold through psychotherapy sessions with Dr. Bormans. During one session, Bormans pushes Claire to confront discrepancies in her storytelling. This prompts Claire to reveal a shocking truth: the images and videos of "Clara" used during her chats with Alex actually belong to her estranged niece, Katia, whom she had once cared for.
Subsequently, Bormans receives a dossier from Claire, containing a narrative where she imagines a different outcome for her story with Alex—what if they were to become live-in partners? However, doubt creeps in as Claire wonders if Alex still holds a place for "Clara" in his heart. The narrative intensifies when, spurred on by her doubts, she decides to reestablish contact and proposes a meeting. But as Alex attempts to reach “Clara,” he discovers the secondary phone that Claire used, leading him to confront her. The confrontation proves destabilizing, causing Claire to stumble back into traffic, presumably leading to her death.
Dr. Bormans, analyzing the unfolding drama, concludes that Claire has a deep-seated reluctance to embrace happiness, even in her writings. As the plot unfolds, it becomes evident that she is a patient in a treatment facility for a mental health disorder.
In a twist of fate, Dr. Bormans later consults Ludovic, who reveals that he had seen through "Clara" when he had heard her voice during calls to Alex. He had fabricated the story of Alex's tragic end. Armed with this new information, Bormans goes back to Claire, who discloses that Gilles had left her for her niece, Katia. Now seemingly prepared to leave the institution, the story reaches a poignant conclusion as Claire uses the phone belonging to "Clara" to dial Alex's number, hinting at a potential continuation of their twisted connection.
