In fourteenth century London, Crispin Guest is a disgraced knight convicted of treason and stripped of his land, title and his honor. He has become known as the “Tracker”—a man who can find anything, can solve any puzzle and, with the help of his apprentice, Jack Tucker, an orphaned street urchin with a thief ’s touch—will do so for a price. But this time, even Crispin is wary of taking on his most recent client. Jacob of Provencal is a Jewish physician at the King’s court, even though all Jews were expelled from England nearly a century before. Jacob wants Crispin to find stolen parchments that might be behind the recent, ongoing, gruesome murders of young boys, parchments that someone might have used to bring forth a demon which now stalks the streets and alleys of London.