Medraut is the eldest son of Artos, high king of Britain and, but for an accident of birth, would be heir to the throne. Instead, his younger half-brother, Lleu, fragile and inexperienced, is chosen. Medraut cannot bear to be commanded and contradicted by this weakling brother who he feels has usurped both his birthright and his father's favor. Torn and bitter, he joins Morgause, the high king's treacherous sister, in a plot to force Artos to forfeit his power and kingdom in exchange for Lleu's life. But this plot soon proves to be much more-a battlefield on which Medraut is forced to decide, for good or evil, where his own allegiance truly lies.