Morgane, the principal of a high school, and her husband Samuel, a restaurant owner, are going through a rough patch in their marriage. They live with their two teenage daughters, Océane and Alizée. The arrival of Hugo Bennec, the school's new PE teacher, disrupts the family's fragile balance. While Océane becomes increasingly fascinated by the charismatic teacher, Morgane also grows closer to him through a shared interest in wing foiling. As emotions deepen, family tensions rise and long-hidden secrets begin to surface.

The investigation into Océane's disappearance intensifies under the leadership of Captain Chloé Rousseau. The first clues seem to point toward Hugo Bennec, whose past and connection to the missing teenager raise troubling questions. As the police struggle to gather solid evidence, both media and institutional pressure mount around Morgane. Convinced that key pieces of the puzzle are being overlooked, she decides to conduct her own investigation, a choice that gradually leads her into increasingly dangerous territory with unpredictable consequences.

The investigation takes a dramatic turn following the discovery of Hugo Bennec's body. Although suspicion initially falls on Morgane, the appearance of a mysterious figure wearing a green hoodie prompts detectives to explore new leads. Meanwhile, Samuel does everything he can to protect his family, while fresh evidence reveals that several people had close ties to both Océane and Hugo. As the case unfolds, investigators uncover unexpected connections that significantly broaden the scope of the investigation and open the door to an entirely new lead.

Just when the investigation seems to be heading toward a resolution, a series of shocking revelations turns everything upside down. Morgane's past resurfaces in an unexpected way and proves to be deeply connected to the case. As hidden identities, old secrets, and misleading clues finally come together, the truth gradually emerges, leading to a tense final confrontation in which Océane's fate hangs in the balance.