First among plot changes is the answer to the age-old question, who was Grendel’s father? We get a clue when Grendel refuses to fight Hrothgar—yup, Hrothgar had yielded to the seductive blandishments of Grendel’s mom in his youth, and Grendel is the result. As we later discover, GM’s children tend to partake somewhat of their father’s nature: Hrothgar is rather a gross troll, spiritually, and that’s what his son is like.
The script is quite faithful to the poem plot.Beowulf decides ahead of time to fight the “unarmed” monster mano-a-mano, since the monster carries no weapons or armor but, as noted, has to resort to mechanical advantage to inflict his fatal wounding—very reasonable given the disparity in sizes.
The plot diverges when Beowulf goes to confront GM in her lair. She is evidently a shapeshifter, since, the bits of her we saw with Grendel were scaly and Gorgonian, but she appears to Beowulf as beautiful and seductive, though still inhuman. Instead of fighting, she offers Beowulf a devil’s bargain; if he gives her a son to replace the one she has lost, and gives her the golden drinking horn he won for killing Grendel, he will reign as a king unvanquishable as long as she has the horn. Beowulf takes the bargain, in part because she has demonstrated that his weapons won’t harm her and she can become immaterial to stay out of his hands. He returns to Heorot bearing Grendel’s head, and claims that he had to leave the sword Hrunding through the mother’s heart in order for her to stay dead. Hrothgar bequeaths Beowulf all his possessions—including Wealthow—and falls to his death from his tower.
We next see Beowulf grown gray in his kingship, as has his Queen (but still smooth faced--) and his remaining old companion, Wiglaf (Brendan Gleeson). Although Beowulf has evidently not made the “mistake” Hrothgar did of confessing that he lay with Grendel’s mother, he and Wealthow have still grown apart due to “too many secrets” between them. Beowulf is jaded since he is unbeatable due to the charm laid on him. All this changes when the golden drinking horn is found by a thrall, abandoned on the heath, which is a sign that the truce is over, and that Beowulf’s own monster son, the dragon, is preparing to throw down with his sire for dominance. The son takes after both his mother, being a golden-skinned shapeshifter, and the dragon form partakes of the strength and inner fire that Beowulf had when he was begotten.
The dragon battle is visually stunning, with much of it being in the air, Beowulf hanging onto the foe by one means or another. He vanquishes the monster, saving Wealthow by moments, but dealing himself a fatal wound in the process, which echoes back to the fight with Grendel. As he lies dying, Beowulf regrets the lies he as told, but Wiglaf maintains that the legend must continue.
Although the settlement has by now become Christianized, (with Unferth now a priest) the fallen hero is given a Viking funeral, with his body surrounded by treasure while his burning ship goes out to sea. Wiglaf, the last watcher, and now wearing the crown, is the only one to see Grendel’s mother, Valkurie-like, claim a kiss from Beowulf’s dead lips as the ship sinks below the waves. The waters wash the golden drinking horn up at Wiglaf’s feet, and Grendel’s mother surfaces and wordlessly transfixes Wiglaf with her seductive gaze*. Holding the horn, he steps uncertainly into the shallows as the sun sinks and the credits roll. (*And Jolie does a really good wordless transfixing seductive gaze: one of the best scenes of acting by sheer expression I’ve seen in a while).
Yes, it is a major change to the Beowulf story, and in some ways actually an improvement. Beowulf’s battle with Grendel’s mother in the poem is very much a replay of the battle in the hall, with the exception that she has the upper hand. The “giant’s sword” that Beowulf kills her with is the oldest deus ex machinas in English literature, and I think finding something to replace is not bad at all. By making Jolie’s character the mother of the dragon as well as Grendel, given her serpent-like characteristics, she becomes Echidna, the Greek monstress who was the mother of Cerberus the hell-hound, the Chimera, and the Hydra among other monsters, connecting the story back even further in time and theme. By connecting Hrothgar’s and Beowulf’s misfortunes to their own failings, we are given plausible reasons why the events of the story happen, instead of just having the monsters motivated out of sheer malice. I was very impressed by Neil Gaiman’s story crafting in “Stardust,” and remain so now.