John Boorman's film is credited as adapted from Malory's Le Morte d'Arthur, and it follows Malory's arc from Uther's night at Tintagel to Camlann: the sword in the stone, the Round Table, Lancelot and Guinevere, the Grail quest and Mordred's rebellion. Its best-known change is at the end, where Perceval rather than Bedivere returns Excalibur to the Lady of the Lake.