During a stay in Paris in 1957, an American girl Clara Foy learns that her mother Lauren had an illegitimate child when she was a teenager living in California. The infant girl was immediately given up for adoption. This event has been kept a guarded secret until the present moment, when the lost little girl comes onto the scene, now a young Parisian woman named Emma Dusel. With the aid of Emma's birth father, an Irish painter now living in Paris named Jack Roman, Clara attempts to bring about a reconciliation between her new sister and her mother. The effort puts Clara's own relationship with her mother in jeopardy, the woman Clara loves more than anyone else.