It's out there, under the salt of the gulf of mexico, off the louisiana coast--a buried nazi submarine. Detective Dave Robicheaux of the new Ibera Sheriff's office has known if its existence since childhood, when he was ...It's out there, under the salt of the gulf of mexico, off the louisiana coast--a buried nazi submarine. Detective Dave Robicheaux of the new Ibera Sheriff's office has known if its existence since childhood, when he was terrified by nightmares of the evil nazi sailors just offshore.