It's the eve of the Civil War, and Glynis Tryon's niece, Bronwen, has joined Pinkerton's Detective Agency. While on her first assignment in the South, two agents are murdered. When word reaches Seneca Falls that Bronwen is in trouble, Glynis heads south -- and finds her niece caught in the midst of a diabolical plot designed to strike at the very heart of the United States government.