A council is held by Lord Elrond of Rivendell, to decide the fate of the one ring between all the free people's of Middle Earth. Frodo volunteers to take the ring to Mordor, to destroy it in the cracks of Mount Doom. However he is not alone, as the Fellowship of the Ring is set up to accompany him on the perilous journey - consisting of the four hobbits, Aragorn, Gandalf, Legolas an elven prince, Gimli the representative of the dwarves, and Boromir on behalf of the men. After failing to travel over the mountains of Caradhras, the fellowship take the pass through the mines of Moria. Sadly on Moria, Gandalf falls to his death after fighting the Balrog. The remainder of the company make their way to Lothlorien, the realm of the Lady Galadriel. After recieving well needed rest and gifts in Lorien, the fellowship once again set out, this time by boat on the great river, Anduin. However they are not safe for long, when they are attacked by orcs.
The fellowship is broken as Boromir is brought to an untimely death from the Uruk-hai. Merry and Pippin are captured and Frodo and Sam decide to take the ring alone to Mount Doom.
In the darkness of Fangorn forest, Merry and Pippin run into Treebeard, an Ent (or tree herder). However as Aragorn, Legolas and Gimli enter the forest, they come across Gandalf the white, reborn again after his fall from Moria. The four of them precede to Rohan to release King Theoden from the grip of Saruman and his servant Grima Wormtongue.
As Frodo, Sam and Gollum continue their journey, they find that the black gate's of Mordor are closed and guarded closely by orcs. Gollum appears to know another way into Mordor though, however they find themselves running into Faramir, the brother of Boromir, and his men from Gondor.
Released from his spell by Gandalf, King Theoden decides to take his people to the safehold of Helm's Deep, to protect them from the advancing orcs. Aragorn, Legolas and Gimli go with them, and Gandalf sets of to gather the Riders of Rohan.
Taken by Faramir's men, Frodo and Sam arrive in Gondor just as the enemy is attacking. Frodo finds his burden getting heavier as the winged Nazgul approach more closely. Meanwhile the Battle of Helm's Deep begins. Luckily the elves turn up due to an old alliance, to help the men defend themselves. The battle continues throughout the night, and just as the alliance starts to retreat, Gandalf and Eomer's riders appear, helping them to ride to victory.
In Fangorn Forest, the Ents are greatly angered by Saruman and his destruction of the forest. Taking Merry and Pippin with them, they advance on Isengard, destroying the dam and flooding Saruman into the tower. Frodo and Sam are meanwhile reunited with Gollum and released by Faramir, leaving them to continue to Mount Doom.
The ring is becoming increasingly more difficult for Frodo to carry as he makes his way closer to Mount Doom with Sam and Smeagol. To make things worse, the sneaky Gollum plans to lead the two hobbits to Shelob, a giant spider. After causing a dispute between Frodo and Sam, Gollum takes Frodo alone into Shelob's lair, leaving him to be attacked and wound into her web. Sam returns to fight her back into her lair, but when finding the poisoned Frodo he believes he has died. As Sam takes Sting (Frodo's faithful sword) and hides from the oncoming Orcs, he overhears them coming across Frodo and taking him up to the tower; realising his fatal mistake.
Denethor, steward of Gondor, is distraught about the death of his son Boromir when Gandalf and Pippin arrive, and refuses to make alliances with Rohan. Pippin swears to Denethor that he will serve Gondor as Boromir died to defend him. Meanwhile the men of Rohan are preparing for war against the dark lord and his armies. Aragorn realises he must take his rightful place on the throne of Gondor when given Isildur's Bane (the sword that defeated Sauron in the last Battle for Middle Earth) and so together with Legolas and Gimli takes the path of the dead to try and regain Gondor's old alliance with the dead King of the Mountains.
As Frodo awakens from the poison of Shelob, he finds himself in the hands of the orcs, completely stripped of all his clothes and possessions, including the ring. As he is coming to terms with this, Sam appears, fighting off the orcs with Sting and rescueing Frodo. It turns out that Sam had taken the ring when he believed his master was dead. Disguised in orc clothing, the pair make their way to the final climb up Mount Doom.
The black gates of Mordor are opened and tens of thousands of orcs make their way to Gondor and the city of Minas Tirith to declare war. Due to the help of Gandalf, Theoden eventually agrees to go to the aid of Gondor with all his riders, and hobbit Merry. As Gondor is seiged, Faramir returns, greatly wounded from battle and is taken for dead by Denethor. Completely stricken with grief from the loss of his two sons, he plans to crimate himself and Faramir. Pippin rescues Faramir from being burnt alive just as Denethor sets fire to himself. Meanwhile on the Pelennor Fields a great battle commences as Rohan, Gondor and the alliance of the dead, fight the enemy for Middle Earth.
Sam and Frodo are close to death from exhaustion when they eventually reach the cracks of Mount Doom, only to find Gollum waiting to take his ring once again. After biting the ring from Frodo's finger, he falls into the lava, killing himself and finally destroying the one ring. This causes the great 'eye' of Sauron to fall and the battle outside the black gates to be won.
Frodo awakes after being rescused from Mount Doom to find the enemy completely destroyed. After Aragorn is finally crowned king and reunited with his beloved Arwen, the four hobbits set of back to their home in the Shire. But after settling back into their daily life, Frodo finds he cannot return to the way he was after the emmense mark the ring has left on him. So together with Gandalf and the remaining ringbearers, he sets sail to the grey havens, leaving Middle Earth forever.