In February of 1861, Abraham Lincoln faced a threat of assassination as he traveled by train from Springfield to Washington for his inauguration. Over thirteen days, legendary detective Allan Pinkerton worked feverishly thwart the plot, assisted by Kate Warne, America's first female private eye. Pinkerton struggled to unravel the details of the plot, even as he contended with Lincoln and his advisors, who refused to believe that the danger was real. With time running out, Pinkerton took a desperate gamble. Shrouded in secrecy -- and later mired in controversy -- the story of the Baltimore Plot is one of the last great untold tales of the Civil War era.