Mary Stewart's final entry in her Arthurian cycle is by far the best of the lot, possibly in part because Merlin is no longer center stage. Since writing the legend from his viewpoint was her stated intent, it's ironic that this should be so. She has taken the bold stand of making Mordred not a villain, but rather an ambitious young man caught up in a web of circumstance, misunderstanding, and political gamesmanship that led him to face Arthur on the battlefield. Nicely done.
'The Wicked Day' is suspenseful and well-paced. Stewart has taken, literally, the stuff of legends and made the conflicts and characters realistic and relatable. This is easily my favorite of her four Arthurian novels, and it could be read as a stand-alone.
The Wicked Day is the gripping story of Mordred, bastard son of King arthur by incest with his half-sister Morgause, witch-queen of Lothian and Orkney. Morgause sent the child to the Orkney Islands to be reared there in secret, in the hope that one day he would become, as Merlin the Enchanter had prophesied, the doom of her hated half-brother.
When Mordred is taken from his rude life as a fisherboy in the islands and suddenly thrust into the full panoply of the High King Arthur's court, he learns of his true parentage and rises to a position of trust in his father's kingdom. But, as the plots and counterplots of the last part of Arthur's reighn unfold, Mordred is drawn into the tangled web of tragedy that is the climactic drama of the Arthurian legend.