André Polonski, a virtuous pianist, and Mika marry for the second time in Lausanne, years after their first, very brief union. In the meantime, André had married Lisbeth who gave him a son, Guillaume. On the day of his sixth birthday, while the family was staying with Mika in Switzerland, Lisbeth died in a car accident. Young Jeanne, who is preparing the Budapest piano competition, happens to learn that she was almost switched on the day of her birth with Guillaume Polonski. In her quest for her origins and a mentor, Jeanne enters the Polonski family that is not her own.