Marty and Rust nail Sheriff Childress based on info they get out of the deputy-now-sheriff they kidnapped. Childress cops to molesting underage girls in occult rituals with Reverend Tuttle that were started by the patriarch Sam Tuttle, who called himself the Yellow King. But they, like old Sam, let the girls go (with threats and promises). They deny that the reverend's cousin(?), Governor-now-Senator Tuttle, was ever involved. But Maggie's father WAS. And Marty's daughter was one girl this circle ritually molested and released.

Marty and Rust confront Maggie's father, who confesses that he was long a part of the circle and then kills himself in front of them before they can do worse to him. But from him, Marty and Rust learn more about Errol, who once participated in the circle's rituals but hasn't in a long time because his behavior became disturbing, even to them. Errol treats his dead grandfather with great reverence and has, unbeknownst to the upscale circle, dug up his corpse and put it on display in the ruins of an abandoned fort called by them Carcosa. There, he and an even darker circle rape and murder girls and boys and prostitutes in their own rituals of purity and impurity, with Errol as the Yellow King. To these rituals, Errol has sometimes invited people like Ledoux and DeWall. But when they try to go after Errol, Marty and Rust are stopped by the agents of, as it turns out, Senator Tuttle.

Marty and Rust, now completely off the reservation, go after Senator Tuttle, and find that he did indeed once participate in the old Tuttle rituals but later came under the influence of Errol. They follow the senator to the remote location of Carcosa, where they find plenty of evidence. But that evidence is burned up when they confront, fight, and kill all the members of the circle amid the raging fire and get wounded (but not so badly). They decide to bury the bodies in the swampy cemetery next to the fort and let the senator's disappearance remain a mystery.

But before they do, they get a final confession from the senator and Errol, who explain that their ritual is the ancient one and Childress' is a corruption of Sam Tuttle's invention. Theirs was handed down for three centuries, when slaves and Indians were sacrificed to elder gods. ("Not the devil. No, much older; much worse.") And there are plenty of old bones and chilling Daguerreotypes around to corroborate their story. Errol and Senator Tuttle claim they "took the rituals back to the old ways, the pure ways." And Errol claims that when they kill him, another Yellow King will arise in his place.