Complex sentence: After discovering the Pendragon is the late King Artorius cursed by the Horned Crown that Morganthe tricked him into wearing (the crown isn't part of the prophecy), you give King Pendragon a potion and the land is restored.
Split into simpler sentences: After discovering the Pendragon is the late King Artorius cursed by the Horned Crown that Morganthe tricked him into wearing (the crown isn't part of the prophecy). You give King Pendragon a potion and the land is restored.