The Riders of Rohan depart for the Fords of Isen, while a great heaviness grows in the air. As they ride, Legolas perceives a cloud rising from Isengard but cannot explain it. Before they reach the ford, a messenger warns of a vast army on the way, so they turn aside to the fortress of Helm's Deep. Gandalf rides off alone to gather news and men while the army defends the fortress, which has never fallen. Thousands of orcs besiege the Deep. Aragorn and Éomer fight bravely at the gates, while Legolas and Gimli compete to see who can kill more orcs. The fighting is hard but not hopeless, until an explosion blows a hole in the wall and orcs overrun the defenses. Théoden resolves to make a desperate charge. As he rides out at dawn, the orc-host discovers a mysterious wood has sprung up behind them. Then Gandalf arrives with more men. Attacked from two sides, the orcs flee into the trees, never to be seen again.
With the battle ended, Gandalf leads Théoden, along with Aragorn, Legolas, and Gimli, to Isengard. As they ride, Gimli describes the marvelous caves behind Helm's Deep, and he agrees to visit Fangorn with Legolas if the elf will visit the caves. When Ents appear, Théoden marvels that children's stories have come to life. The trees depart Helm's Deep and leave behind two mounds over the buried orcs. The king's party passes a pillar with a white hand, now thrown down, and are amazed to find the walls of Isengard in shambles. On a pile of rubble next to the gate, they find Merry and Pippin eating, drinking wine, and smoking Longbottom Leaf from the Shire. The hobbits send Gandalf and Théoden on to Treebeard, but Aragorn, Legolas, and Gimli stay to talk to their friends.
