In January 1919, Dumas Sterling, a Black veteran of the 369th Infantry (the Harlem Hellfighters), returns to Chicago and finds that the war he survived in France has followed him home. After being denied a job with the Chicago Police Department, he opens his own private investigation office. With the help of his wife Celeste, a rootworker from New Orleans, Dumas takes on a series of cases that reveal a sinister undercurrent to the racial tensions and violence simmering in the city.

​As he investigates, Dumas finds himself fighting not only against corrupt officials and brutal gangs, but also against a supernatural entity that feeds on the city's pain and a secret society, the Black Legion, that seeks to tear the veil between worlds. His journey takes him from the trenches of France to the labyrinthine Union Stock Yards, all while his love for Celeste and the hope of a new life fuel his fight against the encroaching darkness. He must use everything he learned in battle, both human and otherworldly, to protect his family and his city from the war that never truly ended