In the 9th century, Mark, King of Cornwall, meets Isolt, the daughter of the King of Ireland, and falls in love with her. He sends his nephew Tristan to deliver his marriage proposal, which, prodded by her father, Isolt accepts. However, crossing over to Cornwall, she and Tristan become lovers. Nevertheless Mark and Isolt marry and soon after the lovers are exposed. The King banishes Tristan from Cornwall but, when he receives news that Tristan is dying of battle wounds in Brittany, he resolves to re-unite the couple.