A story set in the present day, first in a small seaside town in Italy, then, later, in a French village on the Atlantic coast. Marina is a quiet young girl, leading an ordinary life with her father and their family. Although she seems calm and well-balanced, her life is haunted by a tragic secret: the death of her mother, who drowned at sea trying to save her when Marina was only three years old. In any case, that’s the story her father has always told her, although he has always been reticent about the details. For her part, Marina has never dared to tell her father that she has terrible nightmares about this trauma.

After a chance encounter with José, a young French student, Marina begins to take an interest in her mother’s life, about which her father remains obstinately silent. When José sees a photograph of Marina’s mother, he recognizes her as Claudia, a long-forgotten singer who enjoyed a brief but brilliant career 15 years earlier. Although at first reluctant to believe that her father has been lying to her all these years, Marina finally decides to leave for France with José, in the hope of discovering what became of her mother.

Once there, the two young people meet with a number of people who were once close to the singer. They learn that Claudia’s real name was Isabelle – and that she is still alive. So José and Marina head to the village of her birth, where she lives in a small, isolated house with her mother.

It is there that they learn that Isabelle has lost her mind. She has a double personality: sometimes she is Claudia and sometimes Isabelle, and, at any given time, no one knows which one she believes herself to be. After a number of disconcerting episodes, Marina finally remembers the day of the supposed drowning… and she discovers that, in reality, Isabelle wasn’t trying to save her, but quite the opposite…