Britannia, 5th century after Jesus-Christ. Arthur, King of Britain, faces the incomprehension and the reticence of his knights. The doubt settles, the quarrels are more frequent and the failures multiply. The Gods, worried, delegate the Lady of the Lake to maintain the faith of Arthur in his noble mission.

The kingdom is once again assaulted by the enemies, and the rebellion brews among the breton peasants unsatisfied with the government's policy.

Léodagan et his wife Séli, leading dignitaries of Carmélide, try to establish their political power alongside the King by prompting him to give a child to their daughter Guenièvre and a place at the Table Ronde to their son Yvain.

Lancelot of the Lake cannot confess his love to Guenièvre, and slowly distances himself from the other knights and the King.

While the quest for the Holy Grail runs out of steam, Arthur calls his knights up at the Table Ronde.