As I ponder this paradox, I realize how little the Double Eagles interest me. Their motive for murder was one-dimensional. There’s no mystery in atavistic racism. But the Double Eagles almost never operated autonomously. Even before Frank Knox died, they took their cues from Brody Royal. It was Brody who wanted Pooky Wilson dead (for consorting with his daughter), and Brody who authorized killing Albert Norris. It was Brody Royal who lifted Frank Knox out of his drunken grief to try to lure Bobby Kennedy into Carlos Marcello’s sights, and Royal who ordered Snake Knox to make sure Dr. Leland Robb’s plane never reached its destination three years later.

“Goddamn it,” I whisper. “Royal is the key.”

The only real mystery in all this is my father’s stubborn silence. He hasn’t spoken one word about Viola’s death, and he’s flatly denied an intimate relationship with her. To my amazement, he seems as opaque as Brody Royal to me now. All my life, my father has seemed a model of virtue and humility, yet today a childhood memory returned to whisper that he’s also a liar. Caitlin spent most of last night and half of today researching Royal, yet she discovered nothing incriminating on the multimillionaire (who Henry insists is a homicidal monster). How can I resolve these contradictions? If Royal is the sadistic sociopath Henry Sexton believes he is, how could he have concealed it for so long? And if my father isn’t the medical version of Atticus Finch that we all believe him to be … then what is he?

To answer these questions, I need the kind of source that Caitlin couldn’t access with all the power of her father’s media empire, that the police couldn’t match with all their informants and all the information petrifying in dusty file rooms across Mississippi and Louisiana. I need information that lives not on hard disks in remote servers, but in the soft tissue of aging human brains.

And one brain in particular.

Putting the Audi in gear, I back out of my parking space and pull into Commerce Street, driving almost in a trance. A few hours ago, Caitlin said something that’s resonated ever since: “There’s a secret history here …” That phrase always makes me think of Donna Tartt, the Mississippi-born writer, though that title originated with Procopius and his exposé of the crimes of the emperor Justinian. Every small town has its historia arcana, and in Natchez, our secret historian is a woman whom few people have seen in the past ten years. A fabled recluse, she lives with her three servants in one of the finest antebellum mansions in the city. Her name is Pythia Nolan—“Pithy” to her friends—and she’s probably one of the few Natchezians who could read Procopius in the original Attic Greek.