At the Hornburg, the heroes resist a full-scale onslaught of Orcs and Men sent by Saruman, and Gandalf arrives the next morning with the remains of the army of Westfold that Saruman's forces had previously routed.
At the Hornburg, the army of Rohan led by King Theoden and Aragorn resist a full-scale onslaught by the hosts of Saruman. Yet, the tide begins to turn against Rohan, when Gandalf arrives with the remains of the army of Westfold that Saruman's forces had previously routed.