This book tells the story, obscured in a veil of secrecy for 150 years, of the cloak and dagger chess match between Union detectives and Southern operatives in the months before emancipation become effective. Despite an ominous warning by author Herman Melville five years before, the scheme to perpetuate slavery almost succeeded, for it was engineered by a man the National Police Gazette once declared the "King of the Confidence Men."