This book does two things very well. First, the story is fast paced and engaging; each scene moves the action forward. Second, it has a great setting --- one that is well-researched and fascinating. The majority of the story takes place in Washington, D.C., during the Civil War. The author takes the reader into the city at that time. We see the seedy neighborhoods of Southwest, the canal at Georgetown, and the townhouses in downtown DC. As a former DC resident, I appreciated the 150-year look-back into the city.