Course Hero. "The Lord of the Rings Study Guide." Course Hero. 2 Dec. 2016. Web. 20 Nov. 2018. <https://www.coursehero.com/lit/The-Lord-of-the-Rings/>.
Course Hero. (2016, December 2). The Lord of the Rings Study Guide. In Course Hero. Retrieved November 20, 2018, from https://www.coursehero.com/lit/The-Lord-of-the-Rings/
(Course Hero, 2016)
Course Hero. "The Lord of the Rings Study Guide." December 2, 2016. Accessed November 20, 2018. https://www.coursehero.com/lit/The-Lord-of-the-Rings/.
Course Hero, "The Lord of the Rings Study Guide," December 2, 2016, accessed November 20, 2018, https://www.coursehero.com/lit/The-Lord-of-the-Rings/.
Théoden learns enemies are blocking their way to Gondor. He recruits the Wild Men of the Woods who know hidden ways to Minas Tirith to help them circumvent the barrier. As they go along these little-known paths, they find out Denethor's messengers were killed on their way back to Gondor, so Denethor will not know the Rohirrim are coming to assist.
As they near the Pelennor fields where much of the fighting has taken place, they receive the news that Minas Tirith is on fire. Théoden, knowing this battle is probably not going to go well, gives a speech to his soldiers, and they set off for the city. Merry, still riding with Dernhelm, prepares to face battle.
The Riders of Rohan approach and attack Sauron's forces with determination and "battle-fury."
One reason for Denethor's despair seems to become clear here (though it will be even clearer later). He does not believe any help is coming, and therefore thinks the destruction of Gondor is imminent. It does look grim for Minas Tirith; in fact, the city is on fire and may not survive, and even with the reinforcements from Rohan.
Evil's tendency to destroy itself is a recurring idea in the story. The Orcs who captured Merry and Pippin destroyed themselves from within. Similarly, the Orcs who attacked Gondor have broken down the out-wall, allowing the Riders of Rohan to pass through more easily as they rush to aid Minas Tirith. As Éomer says, "Even in this gloom hope gleams again. Our Enemy's devices oft serve us in his despite."