The brilliant young aristocrat William Twining goes hunting through his family's cellar for money after his uncle's business collapses in late-19th-century England, and instead trips a magic circle that summons the demon Dantalion. Dantalion tells him he carries the blood of King Solomon and holds the right to choose Hell's interim ruler while its emperor sleeps: the Elector. A committed realist who refuses to believe any of it, William wants no part of the succession, but Dantalion enrolls at his school and rival candidates like Sytry close in.