The time is 1951. A smooth-talking Chicago lawyer comes to chat with Sam Vincent, the former prosecutor of Polk County, Arkansas, about a dangerous subject—a big prison for violent black convicts near Thebes, Mississippi, up the Yaxahatchee River from Pasagoula. Thebes seems to have dropped out of the Union—letters and phone calls go unanswered, and the lawyer has questions that need answers. Would Sam—an ex-lawman, a white man and a Southerner—agree to go up there and find out what he can?