Crown Jewels.

When a revolution breaks out in a small European monarchy, the king sends his crown jewels to an American banker, Maxwell Grey, to keep them out of danger. However, Madame Levine, the head of an international jewel theft ring, finds out and plans to steal the jewels. She poses as a wealthy society matron and befriends Grey. Young French refugee Diana De Lille, who at first was taken in by Madame Levine, begins to suspect that the woman is not who she says she is, and confides her suspicions to Kenneth Grey, the banker's son, who has fallen in love with her.