Given that you have seen the movies, you may wish to contemplate the prophecy about the death of the Witch-king of Angmar and it's relation to the Barrow Downs.

Given that you have seen the movies, you may wish to contemplate the prophecy about the death of the Witch-king of Angmar and it's relation to the Barrow Downs. A "chance" meeting of the Wight and a rescue by Bombadil where they (not of the race of men) happen to get magic knives woven with the exact ancient spells capable of undoing the Witch-king. The fate of Gondor relied on this piece of the books that is missing in the movies. Without it, the Witch-king isn't killed and they fall to Sauron's minions.