The Road to Isengard
The Road to Isengard is the eighth chapter of the third book in The Two Towers.
King Theoden, Gandalf the white rider, Aragorn, Legolas, Erkenbrand, Eomer, Gimli and the men of Rohan all gather beside a stream. When Theoden asks Gandalf about his wizardry over the trees, Gandalf laughs and tells them that it has not been his doing. He asks them to come with him to Isengard if they wish to know more about the trees.
After resting, the men set forth again. They come to Orthanc, the citadel of Saruman at Isengard. They are surprised to find that Treebeard and his Ents have destroyed the citadel, and that Saruman and Wormtongue have hidden themselves away, guarded by none other than Merry and Pippin. Theoden, who is anxious to see Treebeard, says good-bye to the Hobbits and accompanies Gandalf to the Northern wall.