They ride the long miles from Edoras towards the Fords of the Isen where their patrols have been holding back the enemy. On the second day they are met by a messenger who tells them they come too late. Their forces have been driven back over the Isen and scattered. Erkenbrand of Westfold is retreating back to his fastness at Helm's Deep with the men he can find. Gandalf leaves them on a swift errand, while the rest ride to Helm's Deep. They reach the fortress, the enemy hard at their heels.

Erkenbrand has not arrived, but many men have remained behind to hold Helm's Gate, led by Gamling the Old, and more have escaped there.

Saruman has emptied Isengard and armed the wild hillmen of Dunland. His massed armies mount a great assault using blasting fire to breach the Wall. The fight goes on through the night and, vastly outnumbered, things look grim for the defenders.

At dawn, Théoden and Aragorn lead a great, desperate charge out against the enemy , only to find the orcs suddenly dismayed, as daylight reveals a mysterious wood filling the valley. The Huorns have arrived to deal with the orcs. At the same moment Gandalf appears over the hill, on Shadowfax with Erkenbrand and his men. The enemy is routed. The orcs flee into the waiting shadow of the trees, never to be seen again. Gimli has won his game with Legolas....He has killed fortytwo orcs to Legolas' fortyone.