The third book in the Pendragon Cycle series of Stephen Lawhead is Arthur. The story begins just a few years after the end of Merlin. The godly and strong high king of Briton, Aurelius, the long sought leader who would save the Island of the Mighty, has been murdered through the highest of treachery. His brother Uther takes over to ensure that the gains made through the blood of his many countrymen are not lost. Yet Uther is also struck down. The remaining kings and lords then morph into petty and underhanded politicos to lay claim to Aurelius' throne. The strength, presence, and wisdom of Merlin is all that remains to tentatively hold chaos at bay.
As the divisions in the land run deep, no high king can be chosen at council. Yet the wise Merlin begins to understand the old prophecies regarding the kingdom of summer, a glorious time of peace and prosperity in Britain, led by a king far greater than any who had come before him. That prophecy was to be fulfilled by Aurelius' son Arthur, even though Arthur was still just a young boy. Merlin knew that he had to use all of his powers and cunning to protect the future king and act as his tutor and guide.
The story of Arthur then follows the path of Arthur from his youth, to his leadership of the nation's warband, to his coronation as high king, to his leadership of Britain into a nation of strength, peace, and honor unheard of in its long history. This was the kingdom of summer. Yet, treachery still remained lurking in the shadows for its time. Just at the peak of his realm, Arthur is suddenly brought down and the vacuum created by his sudden disappearance is of an unprecedented power that leaves the land in complete shock. When the light is suddenly doused and darkness takes over, the people finally begin to appreciate just what they had and what they had lost. Now, onto the next book in the series, Pendragon.