Tydorel is a medieval lai which tells the story of a fairy-knight who visits the childless queen of Brittany. He tells her that if she refuses his sexual advances, she will never again know happiness. Then he proves his supernatural origins by riding his horse across the bottom of an enchanted lake and emerging on the other side. He impregnates the queen and commands that she name their child Tydorel. This child is cursed with chronic insomnia, but he is raised by the king and treated as his heir. The queen arranges nightly entertainment for Tydorel since he cannot sleep.