Bowing to an urgent summons from his former lover, Justin de Quincy hastens to Paris only to find that the Lady Claudine was, in fact, acting on behalf of his nemesis Prince John. As the Queen's man, de Quincy has already encountered John's murderous side. But now John tells him of a document implicating him in a plot to kill his brother, King Richard. The document is a forgery, and, despite his hunger for the crown, John is innocent of the charge. Still, a brother who looked with amiable contempt at John's earlier intrigues would hardly risk regicide. John must find the forger and prove the document false before Richard hears of it, and he entreats Justin to help him.

It takes more than John's wily charms to persuade Justin: It is only when he realizes that the welfare of the woman he serves, Eleanor of Aquitaine, is also at risk that Justin concedes. It is a concession that will take him to a bloody chamber on Mont-Saint-Michel, to a stinking dungeon in Brittany, to a murderous encounter in a Paris cemetery, and, ultimately, to the unraveling of a conspiracy that might have changed the course of history.