The Wicked Day, by Mary Stewart, is the fourth and final book in the Arthurian saga. The first three books in this series are The Crystal Cave, The Hollow Hills, and The Last Enchantment. This book fills in what happened in Mordred's life until the time Morgause, upon command of King Arthur, brought him and his step-brothers to Camelot.
He had been raised by a poor couple who made their living by fishing. Mordred helped one of his step-brothers (though he didn't realize the boy was his step-brother at the time) out of a rough spot. To thank him, Morgause had him brought to the castle and told him that he was the bastard son of her husband, King Lot, now dead. She told him that he needed to move into the castle and take his place as a prince. Her lover, sent with Mordred to gather his belongings so that the woman who had raised him wouldn't voice any suspicions she had as to Mordred's parentage, took gifts to the fishing couple, among them some poisoned wine. That night, Morgause had the cottage of the the loving couple who had raised her son as their own burned to the ground.
Mordred grows up in the castle and his step-brothers come to accept him, but they have no clue who he really is. Mordred doesn't even know his own true identity, though he often wonders why Morgause pays special attention to him. Morgause shows just how truly perverted and wicked she is the time she kisses Mordred passionately on the mouth. When King Arthur summons them to Camelot, Mordred fears for his life. His ears have been filled with lies about this great king and he is convinced the man wants him dead. As far as he knows, he is being summoned to certain death.
When thy arrive, Arthur comes out to meet them. A courier ride up and informs Arthur that Merlin is still allive, so he orders Morgause to be taken into custody and her boys to be kept separate from her, but free. They are now to be raised by Arthur and Guinevere. They love their new found freedom from their mother and actually like living at Camelot.
One evening, Mordred discovers that Gabran, Morgause's lover, has a trinket that he made as a child, one that Sula, his mother, always wore around her neck. He then finds out that Gabran took them poison wine at the direction of Morgause and had their cottage burned to the ground. Acting as judge, jury, and executioner, Mordred pulls out his sword and swiftly kills Gabran. When they take Mordred to see Arthur, the boy is afraid for his life. Arthur reveals to him his true parentage, but tells him, for reasons of safety, that he will be known as his nephew. Gawain, Mordred's brother and heir to Lot's kingdoms, will also be told who Mordred's true parents are, but no one else.
Morgause is kept in confinement at a convent, although she is still allowed to do pretty much as she pleases. She meets her doom at the hand of one of her own sons, but not before she reminds Mordred that the death of King Arthur, his father and a man he has grown to love and respect, would come about by his hand.
This really makes Mordred uneasy. How could he bring about the death of his own father? He goes to see Nimue, the wizard who took Merlin's place. Mordred has decided that he will kill himself to keep Arthur from coming to harm. Nimue convinces him that this would not be a wise thing to do.
Through miscommunication and a series of misunderstandings, King Arthur and Mordred do battle one another at the end of the book, but I'm not going to say how their struggle turns out. You will have to read the book yourself to learn this.
This book brings the Arthurian saga to a satisfying end. At the end of the book, there is a note from the author, as well as a recap of the actual legend of Arthur.
I bought my copy of this book from Amazon. If you would like to purchase your own copy, I have provided a link to Amazon below.