
The fellowship begins when the elf, Elrond, the ruler of Elven Haven of Rivendell calls a council meeting to decide what should be done with the Ring as the Ring carries an evil spirit. The Ring can only be destroyed by throwing it into the fires (that is, lava) of Mount Doom, where it was forged. Mount Doom is located in Mordor, near Sauron's fortress of Barad-dûr, and will be an incredibly dangerous journey.
Frodo volunteers to take the Ring to Mount Doom as all the others argue about who should or shouldn't take it. He is accompanied by his hobbit friends and Gandalf, as well as Strider, who is revealed to be Aragorn, the rightful heir to the throne of Gondor. Also travelling with them are the Elf, Legolas, the Dwarf Gimli and Boromir, the son of the Steward of Gondor. Together they comprise the Fellowship of the Ring.
The Fellowship is then set out and the journey begins. They go through many dangerous moments along the journey. Gandalf confronts the Balrog on the bridge, allowing the others to escape the subterranean realm, while he falls with the creature into the abyss below. Boromir tries to take the Ring from Frodo, believing that it is the only way to save his realm. Frodo manages to escape by putting the Ring on his finger. Frodo decides to leave them and go to Mordor alone knowing that the Ring's temptation will be too strong for the Fellowship.
At the later part of the journey, the Fellowship is attacked by Uruk-hai, who Saruman had ordered to hunt down the Fellowship and take back the Ring. Boromir rushes to save Merry and Pippin whom they distract the orcs allowing Frodo to escape, wounded by the orc commander. Aragorn arrives and gives the orcs commander a brief fight. Boromir regrets trying to steal the Ring from Frodo, but is then forgiven by Aragorn. Boromir accepts Aragorn as his king before he dies.
Merry and Pippin are captured by the orcs. Aragorn, Gimli and Legolas begin their pursuit of the orcs in order to rescue Merry and Pippin. Before Frodo departs, Sam decides to join him and together they head off to Mordor.

Frodo awakens from his dream and continues his journey with his trusted and loyal friend, Sam. They meet the ring-possessed, Gollum, who wish to retake "his precious" from the whom he thinks, stole it from him. Realizing they are lost and in need of a guide, Frodo persuades Gollum to lead them to the Black Gate of Mordor.
In Rohan, the Uruk-hai run across the grassy landscape with the captives of Merry and Pippin. Aragorn, Legolas and Gimli, following three days of running. Legolas find out that the Hobbits are being taken to Isengard. Meanwhile, Éomer and his Rohirrim kill all of the Orcs and Uruk-hai holding the two Hobbits captive at nightfall.
During the battle, Merry and Pippin narrowly escape by fleeing into the trees. They are aided by Treebeard, the oldest of the Ents. Upon arriving at the battle site, Aragorn uses his tracking skills and finds hobbit tracks that lead into nearby Fangorn forest. The three discover a wizard who is ultimately Gandalf reborn, now known as Gandalf the White.
Elsewhere, Frodo and Sam are taken to Henneth Annûn and brought before Faramir, the younger brother of Boromir. After knowing about the Ring, Faramir seeks to prove his worth to his father, decides the Ring shall go to Gondor.
The battle of Helm's Deep begins from both human and Elven archers cutting down dozens of Uruk-hai. Scaling ladders are placed upon the Deeping Wall and the Uruks swarm up to engage the defenders. Despite Aragorn and Gimli's best efforts, the Uruk-hai manage to overcome their defenses and penetrate the main door and the stronghold is quickly overrun.
In Fangorn, Treebeard and the other Ents have decided not to have any involvement in the war. With frustration, Pippin takes him to the section of Fangorn Forest Saruman has decimated near Isengard. Treebeard is filled with rage at Saruman's betrayal and commands all other Ents to seek revenge.
Meanwhile, as the Keep is now under attack and realizing Gandalf's words before he departed. Aragorn and the rest make one last ride on horseback to attack the Uruk-hai army, to allow the women and children to escape.
Elsewhere, Frodo narrowly escapes the Ringwraith's efforts to capture him with the help of Sam. Sam tells Frodo how they must go on as Faramir decides to free them to finish their task. Gandalf and the others now know a full war is inevitable as Sauron will surely seek revenge for the defeat of Saruman. Frodo and Sam, resume their journey to Mordor with Gollum. Accompanying them and having felt betrayed after his mistreatment by Faramir's men, Gollum's darker nature returns and decides to reclaim the ring by leading Frodo and Sam to Mordor.

Aragorn, Legolas, Gimli, Gandalf, Théoden and Éomer meet up with Merry, Pippin and Treebeard at Isengard. Pippin's curiosity gets him look into Edoras. He sees a dead white tree in a burning stone courtyard. This alerts Gandalf that Sauron is planning to attack Minas Tirith, and he rides off there with Pippin. Gandalf and Pippin arrive at Minas Tirith to find the steward Denethor.
While climbing the stairs into Mordor at Minas Morgul, Gollum persue Frodo to send Sam home in order to get the Ring back from Frodo.
At the urging of Gandalf, Pippin lights the first of the beacon signals to Edoras, alerting Théoden and the rest of the Rohirrim and prompting them to ride to Dunharrow to prepare for war. Gollum betrays Frodo to the large spider Shelob, but Sam returns to fight her off. Sam thought that Frodo is dead and takes the Ring from him. However, when the Orcs from the Tower of Cirit Ungol take Frodo, Sam heard that he is still alive.
At Minas Tirith, Denethor has gone mad and prepares a funeral pyre for himself and his son, Faramir. Gandalf and Pippin arrive and manage to save Faramir, despite Gandalf's best efforts, Denethor dies. Sam rescues Frodo from Cirith Ungol, following a fight between the two factions of the Tower's Orc garrison, and they begin the long trek across Mordor to Mount Doom. Gandalf realizes that ten thousand Orcs stand between Cirith Ungol and Mount Doom, which will prevent Frodo from reaching his destination. Aragorn proposes they lead the remaining soldiers to the Black Gate to draw the Orcs away from Frodo's path.
Sam carries Frodo up to Mount Doom, but Gollum arrives and attacks them. At the Crack of Doom, Frodo puts the Ring on and disappear from sight instead of dropping the ring into the lava. This act alerts Sauron, and sends the Ringwraiths racing towards Mount Doom. Gollum then suddenly appears and seizes Frodo's finger, and bites it off. As he begins to celebrate reclaiming the ring, Frodo uses his strength to attack Gollum.
After they struggle, they both fall over the edge. Gollum falls into the lava flow with the Ring, while Frodo hangs onto the edge of the cliff. Sam rescues Frodo as the Ring finally sinks into the lava and is destroyed.
The Tower of Barad-dûr collapses, Sauron's essence fades and then explodes and the Orcs, Ringwraiths and the remaining forces of Sauron are killed in the shockwave and earthquakes. Frodo and Sam are stranded as Mount Doom erupts. Gandalf arrives with the Eagles, and they awake in Minas Tirith, reuniting with their friends.
Aragorn is crowned King, and is reunited with his long-time girlfriend, Arwen. The hobbits return to the Shire, where Sam marries Rosie Cotton. Frodo finishes his story writing of the Lord of the Rings. He still feels exhausted from his quest as the Ring-bearer, decides to leave Middle-earth with Gandalf, Bilbo, Elrond and Galadriel at the Grey Havens, leaving his account of the story to Sam, who peacefully continues his family life.