Lady Marguerite Blakeney, formerly Marguerite St. Just, is the wife of Sir Percy. Young, beautiful, clever, and talented, Marguerite was an extremely popular French actress in Paris before she married the English milor. At first, she is a Republican, and a supporter of the Revolutionary ideas. However, she is used by agents of the Republic to bring about the deaths of an aristocratic family. This causes her to be estranged from her husband, who feels he cannot trust her with his greatest secret. But after many trials and tribulations, all is brought to a happy conclusion.