With Gollum/Smeagol as a guide, Frodo and Sam gets nearer and nearer to Mordor. Sam figures out Gollum's treachery and tries to convince Frodo that Gollum is evil. Sam and Gollum are both trying to get trusted by Frodo. However, Frodo comes to a conclusion that Gollum is nicer and shoos Sam. However, Frodo later learns that Gollum is the evil one. Frodo throws Gollum down an opening in the earth. Shelob the spider stings Frodo but does not have a chance to devour him, for Sam has come. Frodo was alive but taken by the enemy. Sam follows the unconscious Frodo to the dark tower of Cirith Ungol. There, Sam saves Frodo and they set off for Mount Doom. However, they must get across the Plains of Gorgoroth that is infested with orcs.
Pippin finds a watching-stone (Palantir) in the flooded Isengard. Gandalf brings it back to Edoras. Tempted, Pippin secretly looks into the Palantir. He sees the Dark Lord's plan: to destroy Minas Tirith, the chief city of Gondor. Gandalf decides that he will go to Minas Tirith with Pippin.
Arwen is on her "last" journey towards the shore when she sees a vision of her son. She turns back and goes to Rivendell. She insists that the Blade that was Broken be reforged. Elrond, now knowing that Arwen will not leave Aragorn, reforges the sword.
When the first attacks begin to take place, Gandalf has Pippin light the beacons of Gondor. The beacons reach Edoras, where the king decides that Rohan will go to war. Eowyn comes with them, "only to say farewell." So does Merry. The Rohirrim muster at the side of a dark and ominous mountain. Aragorn receives the Sword of the King by Elrond and decides to go to the Paths of the Dead. There, he commanded a dead army to fight for him.
Gondor get sieged, and Denethor goes mad. He attempts to burn Faramir and himself, not knowing that Faramir is alive. Gandalf, with help of Pippin, saves Faramir, but Denethor passes away. Then, a horn is blown, announcing the arrival of Rohan. The Riders of Rohan (and Eowyn) ride through the army of Mordor. Hope seems near. However, a fleet of Corsair Ships arrive. All thinks that this is another army for Mordor, but out jumps Aragorn. The army of orcs are defeated. The Men of Rohan and Gondor decide to march to the Black Gate of Mordor. There, they would bring out the army and give Frodo and Sam a safe passage.
Not knowing what has happened outside, Frodo and Sam continue their trek. They get on the slopes of Mount Doom, but is attacked by Gollum. Frodo runs into the Mountain.
The army of Men of the West at the Black Gate is helped by huge eagles.
Frodo puts on the Ring, but Gollum bites off the finger. Gollum dances of joy, but Frodo has not given up yet. He jumps at Gollum and ends up in the brink of a stretch of rock, hanging. Sam pulls him up. Sam helps Frodo outside the mountain, but they are trapped on an island of ash pile.
Gandalf, riding an eagle, comes to save Sam and Frodo.
Sam and Frodo wakes up in Gondor, where Aragorn is crowned. Aragorn is now the King of Gondor. Arwen and Aragorn get married. When the hobbits bow to Aragorn, Aragorn says "My friends. You bow to no one."
The whole population of Gondor bows at the hobbits. The hobbits return to their home-country, the Shire. Sam marries Rosie Cotton. However, poisoned by Shelob and the Morgul Blade, decides to go to the Undying Lands.