The escapades of a young woman who has unfortunately directed her great abilities to a course of criminal theft. Starting with a carefully mapped out robbery of the various guests at a party to which she has been invited, she successfully makes away with her friends' valuables and pocketbooks. This is followed by her planning a diamond robbery, which could only emanate from a fertile brain. She enters a jewelry store and asks to see some diamonds that are in the window. The clerk takes the precaution of counting them, and then hands the tray for inspection. Unseen she withdraws from her mouth some gum which she has purchased for the purpose and, taking a diamond, secretes it on the underside of the counter by using the gum for the purpose. On her preparing to go the clerk finds a diamond missing and has her searched, but without avail. She is next seen to enter the jewelry store in man's attire, and under the pretense of wanting to buy a watch, awaits her chance and removes the diamond, which has remained unmolested. She next holds up a bank messenger, with the contents of whose valise she has already been cunning enough to become acquainted. Once more in male attire, she produces her gun and relieves the messenger of the valuables his precious valise contains, and on a policeman entering the scene she turns her gun on him and holds them both at bay, while she makes her escape. The final scene is then enacted. The female highwayman, thinking she has successfully eluded her pursuers, proceeds to enter her room and dispose of the valuables she has on her person. While doing so she hears noises of her pursuers, who break into her room and capture her at last.