Siege of the Hornburg Castle
The Uruk-Hai of Saruman started to set up the siege ladders and started to climb the walls of the Hornburg Castle. The fighters of Rohan, elves (in the movie) along with Gimli, Legolas and Aragorn successfully warded off the Uruk-hai army at first.
Culvert of the Hornburg Castle – Weakness of Helm’s Deep defense
In the novel, the uruk-hai has dug through the culvert and this wasn’t referred to as a weakness by Grima Wormtongue.
In the movie, Grima Wormtongue mentions the sewer like culvert where a small stream flowed from the Hornburg castle that it was the weakness of the Deeping Walls of the Hornburg Castle.
Saruman prepares the Fire of Orthanc also known as Saruman’s Devilry. Although the Hornburg Castle was built by Gondor, it seemed that the masonry of Numenor wasn’t utilized or probably lost at the time the castle was built so the Hornburg Castle wasn’t as firm and solid as other castles built by Gondor.
Devilry of Saruman / Fire of Orthanc
The Fire of Orthanc or the Devilry of Saruman was only described as magic without detailed information in the novel. In the movie, the Fire of Orthanc was adapted to be bombs filled with black gun powder.
An uruk-hai berserker carries a fire probably brought from Orthanc to light up the Fire of Orthanc that would blow up the Deeping Walls of the Hornburg Castle that was depicted as running wiht a torch. Legolas made some shots onto the uruk-hai, however the uruk-hai successfully dived into the Fire of Orthanc blowing up a massive chunk of the Deeping Walls.
Destruction of the Deeping Halls and retreat to the keep and the Glittering Caves
By the explosion of the Fire of Orthanc, chunks of the Deeping Walls of the Hornburg Castle blew up and the uruk-hai army breached inside the Hornburg Castle.
Theoden and the defenders had to retreat inside the Glittering Caves and they kept defending the Hornburg Castle. Haldir dies during the defense.
In the movie, king the breach of the Deeping Walls discouraged king Theoden; however, Aragorn encourages king Theoden to ride out to ward off the uruk-hai.
In the movie, Aragorn remembered the words of Gandalf before Gandalf went searching for Eomer(In the novel, Aragorn searches for Erkenbrand, the marshal that succeeds Theodred after Theodred’s death. Erkenbrand took command of the forces of Rohan of the westfold in the novel while Eomer participated the Battle of the Hornburg Castle from the first)
Aragorn seeks for one last hope, as the 5th day of Dawn since Gandalf left Theoden, Gimli, Legolas and Aragorn was coming.
Theoden’s Stand
King Theoden makes the final charge outside the Hornburg Castle leading his cavalry just before dawn.
In the movie, Gimli also blew the horn of Helm Hammerhand that boosted the morale of the cavalry making their last charge.
The Uruk-hai were pushed back a bit, however still the uruk-hai vastly outnumbered the defenders of Helm’s Deep. However at the east ridge of Helm’s Deep, Gandalf stood with his horse shadowfax.
Aragorn recalls Gandalf’s words. “Look to my coming at first light on the fifth day. At dawn, look to the East.”
Reinforcement and the Charge of Gandalf and Eomer
In the novel, instead of Eomer, the marshal Erkenbrand came to the rescue and the men weren’t cavalry but infantry.
In the movie, Gandalf went searching for Eomer that was banished from Edoras by the plot of Grima Wormtongue.
Theoden King stands alone
Not Alone. Rohirrim! To the King!
- Eomer and Gandalf –
Gandalf found Eomer and the eored(company unit for Rohan army) and they’ve rallied up the rohirrim of the westfold about 2,000 cavalry to relief Helm’s Deep. Eomer and Gandalf charge against the uruk-hai turning the tides of the Battle of the Hornburg Castle.
The massive flank attack by the cavalry that didn’t fear pikes and long spears took down the uruk-hai army that wasn’t in proper formation. The uruk-hai’s retreats and Theoden claims victory.
Gimli and Legolas's bet - who killed more uruk-hai
Gimli and Legolas made a bet and kept the score of the kills of uruk-hai they made. Gimli claims he killed 43 while Legolas claimed he killed 42.
Forest in front of Helm’s Deep – Huorns
The huorns, living tree spirits have already assembled in front of Helm’s Deep. The Rohirrim, Legolas, Aragorn, Gimli, Gandalf and Theoden with Eomer notices an unusual forest that suddenly appeared in front of Helm’s Deep while they were in pursuit of the retreating uruk-hai(forces of Saruman.
In the novel, only 300 Dunlendings survive and Theoden forgives them and releases them.
Also, the migration of the huorns were also noted in the novel). The uruk-hai relentlessly entered the forests of the huorns and the huorns, the living tree spirits crushed the remaining uruk-hai.
Last March of the Ents and the Battle of Isengard
In the novel, by the entmoot, the ents and Treebeard decided to take action and attack Isengard. The huorns the living tree spirits also joined the ents and attacked Isengard.
The main forces of Isengard were already in assault of the Hornburg Castle so the ents and the huorn easily overrun the fortress of Isengard.
In the movie, the entmoot decided to remain neutral but Merry and Pippin were able to lure Treebeard to the deforested regions of the Fangorn Forest.
Treebeard was talking about the mice that tickled him but witnessed the devastated lands of the Fangorn Forest by Isengard.
Merry and Pippin eventually was able to convince Treebeard to join the cause against Saruman. Treebeard, who was once a close friend of Saruman, was in a rage and makes a battle cry that calls upon the ents and huorns.
By the last march of the ents, the dams that blocked the isen river were destroyed and the land of Isengard was flooded.
The ents took down the dam so the forest of Nan Curuinr could grow back while the flood also destroyed the forges and structures built by the orcs and Saruman.
The ents sieged Isengard and the tower of Orthanc while Saruman was forced to be locked up in the tower of Orthanc.
