Baroness Lilian registers at a hotel and is promptly arrested because she looks so much like the jewel thief Yvette. However, when the jeweller who stole the jewels mentions that the real thief had a dark spot on her thigh, Lilian, who is missing that very spot, is exonerated. When the elegant Erik Termeulen also mistakes her for the criminal, Lilian decides to put an end to the confusion and track down her doppelganger. She meets the real Yvette in Nice and learns that a gang is after Erik’s jewels.