The Old West finally died in 1980. But we're in Texas, and it's 1978. This is the story of Grissom Callahan, the last in a long line of sheriffs. Callahan learned everything he knows from his father and grandfather, but the ways of the old regime don't prove effective when a violent killer emerges in their small town. In a single moment of shaking down an informant, Grissom triggers a chain of events that will reshape his life and the world of Texas law enforcement.