Everything you need to understand or teach Underground Airlines by Ben H. Winters.
Ben Winters's 2016 alternate history/noir-detective/conspiracy thriller Underground Airways takes place in an alternate reality based upon the absence of one of the United States's most important historical events: The Civil War. In the world of Underground Airways, slavery has infected the United States over the past centuries, permeating the lives of most Americans who regard the continued practice of slavery in four southern states without much regard until a group of citizens known as the Underground Airways come forward to try and make a difference - or so it seems. The novel tells the story of Victor, a former slave and current U.S. Marshal tasked with hunting down and capturing escaped slaves and attempting to dismantle the Underground Airways network. However, while hunting for an escaped slave named Jackdaw, Victor finds himself drawn in a conspiracy that threatens to make slavery a permanent institution throughout the United States. The novel explores a wide variety of themes, including self-discovery, the nature of history and the power one person has to effect the outcome of history.