The Earl of Selkirk and his family learn of the impending arrival of American pirate John Paul Jones, they flee their castle, leaving behind Nora, the kitchen maid. Left alone in the house, Nora dons the clothes of her mistress and parades herself about the castle until the arrival of the king's light infantry. Because they mistake her for the lady of the house, she invites them to be her guests.

Promising young lawyer Jack Dunn,, becomes a victim of drugs and loses his standing in the legal world. He passes his idle hours in the slums where he meets Nan Bishop, an underworld figure. Nan's influence helps to make a man out of Dunn and with her help he breaks his dependence on drugs and is successful in obtaining a position as a criminal lawyer. Years later, they meet again in a courtroom. Nan has been falsely accused of murder and Dunn is the prosecuting attorney. Learning that Dunn's professional future depends on his winning the case, Nan pleads guilty, but, at the last minute, the real criminal is discovered and Nan is cleared of the crime. She then accepts Dunn's offer of marriage and together they look forward to a happy future.