Set in the Dark Ages a century after the Roman withdrawal from Britain and during the Anglo-Saxon settlement of Britain, Arthur is not a glamorous king with an elaborate court; instead, he is (as presumed by some historians[1]) just a Celtic leader who installs and maintains a Celtic alliance against the Saxon invaders.

He is instructed by his adoptive father Llud and assisted by Kai, a Saxon orphan reared as Arthur's brother.

Cerdig, chieftain of the Saxons, is Arthur's principal counterpart who in the episode "The Treaty" even insults him as a man "with many brothers but no father" but learns to respect him in the end.

The series dispenses with the legendary Round Table and popular figures such as Merlin, Guinevere and Lancelot and attaches no significance to magic or superstition.

While some films about him avoid the question of his origin and show him as a man who defends Christian Britain against heathen barbarians out of a sense of integrity, this TV show portrays him as one of the Britons who were already in Great Britain before the Romans, Anglo-Saxons and Normans came, and hence, a Celt defending his homeland.

Their villages are in the middle of their fields and they are not fortified, since they can recognise approaching enemies earlier than the Celts who live in glades.

(In the first episode, called "Arthur is dead", the gathered Celtic leaders beseech their gods to help them to tackle a task.

Arthur seeks to forge an effective Celtic alliance in spite of religious differences, rivalry and sheer animosity among the leaders.

Once Arthur has accomplished his political goals and provided the grounds for peace, he indulges himself to the pursuit of personal happiness.

Many iterations of Arthurian legend end with Arthur's death or severe wounding by Mordred's hand at the Battle of Camlann.

In the penultimate episode, under threat of attack by the Scots, Arthur comes close to securing a treaty between himself, Cerdig and Yorath the Jute, but a carelessly placed target board results in a death, and old hostilities quickly re-surface.