A high school French teacher, Germain, discovers an unusual talent in one of his students, Claude, after assigning his class to write a paper about their weekend. Claude's essays articulate his clandestine observations of a classmate's middle-class home life. Intrigued by the voyeuristic insights, Germain becomes both mentor and enabler to Claude, encouraging him to continue his written "invasions." As Claude becomes increasingly integrated into the family's household under false pretenses—befriending Rapha, the classmate, and ingratiating himself with Rapha's parents—the lines between mentorship and complicity are blurred. Germain's initial academic interest morphs into an ethical quandary as he is drawn deeper into the adolescent's manipulative storytelling.

Meanwhile, as the written accounts ascend in intimacy and complexity, Germain's wife, Jeanne, a contemporary art gallery curator dealing with her own career frustrations, becomes an audience to Claude's stories. She is both captivated and unsettled by the unfolding narrative. Germain's obsession with his protégé's writing starts to consume him, undermining the stability of his professional life and the foundation of his marriage. The teacher's fixation on raw storytelling talent becomes a dangerous game as it exposes the vulnerability of the family being chronicled and ignites tensions within Germain's personal life. The consequences of voyeurism, influence, and the blending of life with art begin to ripple through the lives of all involved.