Gerard Buckland, a young society man, sees a pretty girl on the street. While speculating on her family connections, he sees a shady-looking man hand the girl a diamond necklace, which she conceals before vanishing into the crowd. Later, at the home of a friend, he is amazed to meet the girl, who is as charming in conversation as she is in appearance and manner. To entertain her friends, she picks their pockets with professional skill, later returning the property with laughter. Miss Davison claims to be employed as a designer, but Buckland becomes convinced that she is either a kleptomaniac or an accomplice of the elderly man he often sees her meet. Miss Davison is neither of these, however, but is instead the best woman detective in New York. The mysterious old man is, in fact, her chief. The truth comes out at the Van Santen party when Miss Davison reveals herself as a detective and exposes the Van Santens as international crooks who have been preying on the rich. They are brought to justice through evidence gleaned by Miss Davison; and Buckland, radically revising his opinion of her, begins an ardent courtship.