Bilbo Baggins, the main character of The Hobbit, still lives at Bag End in the Shire. He and his nephew Frodo are celebrating their birthdays, so they are having a big party. Bilbo decides to uses his Ring, which makes him invisible. He vanishes before the eyes of the guests. After protests, the Ring has already taken his mind, Bilbo gives the Ring to Frodo. 
Gandalf, the grey magician, is worried about the Ring because he suspects that it is the One Evil Ring made by the wicked lord Sauron long ago. Gandalf's worries are not unfounded, for Middle Earth has
fallen on dark times and ominous things are happening. The mighty forest Greenwood is haunted by evil powers and now goes by the name of Mirkwood. Driven out of Mirkwood by the White Council of Elves, the forces of darkness assemble in Mordor, the "home" of Sauron. 
Gandalf tests the Ring and sees that this is indeed the One. He tells the brief history of the Ring: The Ring was made by Sauron. Elendil overthrew Sauron, but he died. This is the end of the Second Age. His son Isildur took the Ring. The Ring fell into the Anduin, the Great River. It was there until Deagol found it when he was fishing. His friend Smeagol, a hobbit, killed him for the Ring. He had the Ring until his "riddle quest" with Bilbo, which is told in The Hobbit. 
Sauron now knows that the Ring isn't destroyed and he wants is back, which would mean the end of Middle Earth. The only way to destroy it is to cast it into Mount Doom, where Sauron made the Ring. Sam, who lives in Bag End also, heard a lot. 
20 years later Frodo decides to sell Bag End to his neighbors, who have always wanted the hole. He has bought a new home. Pippin and Sam accompany him to his new home. Gandalf should accompany them but he hasn't showed up. They are walking on the Road, when the Black Riders pass by. They hide in the bushes. The horses are sniffling to detect Frodo and Frodo has a strong desire to put on the Ring but he doesn't do it. After that they meet Elves. After Gildor, the "main"Elf, heard what happened they decide that they must travel together. Frodo asks all about the Black Riders, but gets little response. 
Frodo decides to take a short cut, but they get lost. They enter the land of farmer Maggot, who still remembers Frodo for the stealing of mushrooms years ago. Maggot tells that a Rider has passed by, seeking for Baggins. Maggot brings them to the Ferry. Frodo, Sam and Pippin go to Frodo's new home where they meet Merry. Frodo hears that his 3 companions now quite a lot of the Ring, thanks to Sam. 
Their voyage continues through the Old Forest where Merry is caught by a tree. Tom Bombadil, as old as the world and master of the Old Forest, passes by and tells the tree to release Merry. They follow Tom to his house. There they rest and learn that Tom doesn't become invisible when he puts the Ring on. They leave Tom's house and short after that, Frodo is caught by a wight in the fog. Tom helps them again and puts them back on the Road. They go to The Prancing Pony an inn in Bree, a little town. Frodo = Mr. Underhill. Frodo dances on the tables and falls. He is ashamed and puts the Ring on. He goes to a corner where Strider, a Ranger, is sitting. Now everybody knows that Mr. Underhill is special. Strider warns him for that. Strider wants to go with them but Frodo doesn't trust him. Frodo sees a letter of Gandalf, which Mr. Butterbur, the innkeeper, ought to send him, in which he reads that Strider is a friend of Gandalf. He knows that Strider is the real Strider since Strider says his real name and a poem, which is also written in the letter. 
Black Riders have entered Bree, so Strider wants to make for Weatherthop the next day. He hopes to meet Gandalf there. Nobody has heard of Gandalf and they fear the worst. 
Merry's ponies are stolen so the buy a pony of Bill Ferny, a brute. The leave for Weathertop and pass through a swamp. They reach Weathertop, where the meet Black Riders. Frodo is afraid and puts on the Ring. Now he is visible for the Riders and is attacked by a knife in his shoulder. Frodo is badly wounded and can only be healed by Elrond. They meet Glorfindel, a friend of Elrond. Black Riders are coming so Frodo leaves on Glorfindels's horse. He passes a ford, where the Black Riders are overwhelmed by the sudden water. 

Book II 

Frodo is in Rivendell, the house of Elrond. His wound is cured by Elrond. There is a Council: Many delegates from Elves and Dwarves are gathered and Frodo learns a lot more about the war of the Ring. Boromir, who came from Gondor, tells that Gondor is still holding out against the rising power of Mordor, nut is badly in need of help. Aragorn (= Strider) tells that he is the rightful king of Gondor. Gandalf tells that Saruman, his chief, has turned traitor. Saruman wants to have the Ring for his own. He has locked Gandalf up in Orthanc, his "home". Gandalf managed to escape with help of the Eagles. He went to Rohan as a beggar and returned with Shadowfax, a horse, which Theoden, the king of Rohan, had "given" him ( take anything, but leave). The Council decides that the Ring must be destroyed in Mount Doom. Frodo is the only volunteer. A Fellowship is formed to help him on his travel. Gandalf, Aragorn, Boromir, Legolas, Gimli, Sam, Merry, Pippin and the Bill Ferny's pony Bill go with him. 
They are watched while they pass the heavy snowed mountain Caradhas. After that they enter the Mines of Moria through a secret entrance. In Moria mithril is found, of which Frodo has a coat, given to him by Bilbo. Bill stays behind and is sent back for Rivendell. They see the grave of Balin. They are attacked by Orcs but Gandalf withstands them. Frodo is hit by an arrow, but the mithril coat saves him. A Balrog, the most fearful opponent of all, attacks them. Gandalf and the Balrog fight on the bridge of Khazad- dm. They both fall down and vanish. 
Aragorn becomes the leader of the Fellowship. They go to Lothlorien, a forest where Elves live. Gimli the Dwarf must enter blindfolded but doesn't want to, so everyone enters blindfolded. After that Hadldir, the Elf who accompanied them got a message from Lady Galadriel, they may all see. 
They meet Celeborn and Lady Galadriel. Frodo looks into the mirror of Galadriel, a magic mirror, in which he sees a searching Eye. Frodo, frightened, turns back. Frodo sees that Galadriel is also a Ring-bearer. The others can't see her Ring. Galadriel advises them to use the Anduin, so she gives them boats. She also gives them lembas, a sort of food. She gives Aragorn an Elfstone, Sam a box for his garden and Frodo a vial which gives light when all other lights are gone. 
They continue their travel by boat. They suspect that Gollum (=Smeagol) is behind them. Frodo has to decide which way to go, to Minas Tirith, as is the strong wish of Boromir, or to Mordor. Boromir tries to take the Ring by force. Frodo puts on the Ring and leaves them by boat. Sam goes with him. The others remain seeking for Frodo. They split up. 

Part Two: The Two Towers 

Book III 

Boromir defends Merry and Pippin against an attack of Orcs and followers of Saruman, but dies in battle. Aragorn finds Boromir and puts him in a boat. The boat flows on the Anduin. Merry and Pippin are taken by the Orcs, the Uruk-hai. Aragorn, Gimli and Legolas go after them. On their pursuit they meet Eomor and other Riders of Rohan. Eomor has slain the Orcs but has seen now hobbits. Still they go on, with help of horses lent by Eomor. They reach Fangorn, where the battle took place. As they rest their horses are stolen by (who they suspect) Saruman. In the meanwhile Merry and Pippin are captured by the Orcs. They are not killed since Saruman wants halflings(=hobbits). In Fangorn they tell their guards that he can have the Ring if he unties them. The guard does so, but Merry and Pippin flee into Fangorn. Merry and Pippin meet Treebeard, an Ent . Ent are the Shepherds of Trees, Treebeard tells them the story of Ents: the Entwives are gone so there aren't much Ents left. The Ents are angry with Saruman, since he has brought Orcs in their country(Fangorn). After a meeting of Ents, they go to Isengard, Saruman's home. 
Aragorn, Gimli and Legolas also go into Fangorn, where they meet Gandalf. Gandalf has now become Gandalf the White instead of Gandalf the Grey. Gandalf is sent back to Middle Earth from the underworld to fulfill his task. They all go to Theoden, king of Rohan. They ask him to join them on their road to Isengard. Grima the Wormtongue, the advisor of Theoden and the person who sent Eomor in prison, doesn't want that. Gandalf recognizes him as a servant of Saruman and sends him away. 
They go to Helm's Deep, but Gandalf goes directly to Isengard. The battle at Helm's Deep with the Orcs goes ill until Theoden decides to ride forth and make a path. Gimli and Legolas, who have become close friends, are holding a competition in which they look who has slain the most Orcs. Gimli wins. They go Isengard where they meet Merry and Pippin who tell them that the Ents have overthrown Saruman. The Ents have locked Saruman and Wormtongue up in Orthanc. Gandalf, who is now a magician of a higher rank, Saruman's superior, breaks Saruman's magic staff and expels him from the order of magicians. Grima throws a magic crystal, the palantir, at Gandalf, who is not hurt. Pippin picks it up and gives it to Gandalf. Later he has a strong desire to look in it and when the others are asleep, he looks. He sees Sauron, who himself thinks that Saruman has captured the hobbit. Pippin screams and so Gandalf finds out. The link between Isengard and Mordor is explained. Gandalf leaves the company after he saw the Nazgul , the flying Black Riders, and makes for Minas Tirith as fast as Shadowfax, his horse and master of horses, can bear them. 

Book IV 

Frodo and Sam continue their travel to Mordor. They meet Gollum. They want him to go with them, so they tie him with Sam's Elfrope. Gollum can't stand that, so he swears by his Precious, the Ring, to be good. Gollum leads them through the Dead Marshes. When the rest, Sam hears Gollum talking to himself that he wants the Ring. He says that She (Shelob) might help. 
Gollum leads them to the Gate of Mordor, which is closed. Gollum knows another, secret, way. Frodo decides to trust him. They meet Faramir, Boromir's brother. Frodo tells them who he is and by accident Sam tells about the Ring. Faramir doesn't want the Ring. Faramir sees Gollum in a forbidden pool. The rule is that he must be killed, but Frodo helps Gollum and will look after him. Faramir gives them food and leaves. 
Gollum lead them to the stairs of Cirith Ungol, the secret way. Frodo has a difficult time, since every step he comes near Mount Doom, the burden of the Ring becomes heavier. They pass through a long and dark tunnel. Gollum is gone. He probably had a deal with Shelob. He the Ring, She the hobbits. Frodo and Sam are attacked by Shelob, a giant spider. Frodo uses the vial and drives Shelob back. But eventually she wins and poison's him. Gollum attacks Sam, but Sam beats him off. He realizes that Frodo must be dead and with all the power he has, he beats Shelob off. In despair, Sam realizes that he is only one left to complete the Quest of the Ring. he takes the Ring from Frodo and prepares to go alone. But before he leaves, Frodo's body is found by Orcs. Sam slips on the Ring and follows them. He learns that Frodo is not dead, only poisoned. Sam doesn't know what to do, but he decides to try and rescue Frodo. As he stand deliberating, the Orcs carry Frodo's body inside the fortress and shut the gates. 

Part Three: The Return of the King 

Book V 

Gandalf and Pippin arrive in the capital of Gondor, Minas Tirith, where they are received by Denethor, who rules the country as Steward of the lost King. They face the difficult task of informing Denethor that his son, Boromir, is dead. Denethor asks Pippin all about Boromir. Gandalf tells Pippin not to tell anything about Aragorn, the rightful King of Gondor. When Aragorn comes and claims his kingship, then Denethor must resign. Pippin offers his services to Denethor, who accepts them. Pippin is sent away and meets a soldier of Gondor, Beregond, with whom he goes to the City Walls to look at the arrival of armies. They see that there are too few of them to resist the terrible might of Mordor. The fate of Gondor depends on the help of the men of Rohan. If they don't make it in time Gondor will be faced with ruin and destruction. 
The company of Aragorn and Theoden have help from other Rangers, the Dunadain. When Aragorn looks into Saruman's magic crystal (it is his) he sees that war is about to break out in Gondor and decides that he must hurry. With the Dunadain and Legolas and Gimli he decides to take a short cut through the Paths of the Dead. This is a path in which people lie which have a promise to keep: they must do something against Sauron ere they have rest. Aragorn has the power to give them that rest, so the dead let him pass. Meanwhile, Merry offers his services to Theoden, who accepts them. A bit later, Theoden tells Merry that he can't go further with him. Merry gets help form a soldier Dernhelm, who hides Merry under his jacket. Dernhelm turns out to be Eowyn, sister of Eomor who also wasn't allowed to go with Theoden. She had to stay in Rohan and govern the land. 
In Gondor the war begins before Aragorn and his men arrive. The paralyzing magic of Sauron weakens the will of the defenders. Fearful onslaughts by the forces of Mordor are repulsed, but the men of Gondor suffer heavy losses and are in low spirits. Denethor, grieving over his son Faramir, who returned and was sent to defend the passing of the Anduin and came back wounded and is almost dead withdraws. Gandalf now commands Gondor. The battle goes ill and all seems lost. But then the men of Rohan, who have taken a short cut with help of the Wild Men, appear and throw themselves into battle at last. King Theoden dies a valiant death and also Eowyn does some great things: she is responsible for the dead of the head of the Nazgul, but she is now heavily wounded. The battle goes ill again but then Aragorn and his men arrive. The forces of Mordor are beaten back. Denethor has sunk into a deep depression from which nothing can rouse him. His son Faramir, who is supposed to be dead, is laid on a funeral pyre, but at the very last moment Gandalf leaps forward and pulls the young man out of the flames. He is still alive. His crazed father throws himself into the flames and is burnt to death. Gandalf finds out that Denethor had become insane through using a magic crystal just like the one Saruman kept at Orthanc. By means of the crystal, Saruman had worked his evil power on Denethor's mind. Young Faramir is cured by the King's Touch when Aragorn, the rightful King, lays his healing hand on him and treats him with herbs, which they found after a long search. Aragorn also heals Merry and Eowyn. The people of Gondor know that the rightful King has returned. 
Gandalf realizes that the Eye, which is searching for the Ring, must be somewhere else then in his own land. He goes to battle and with him thousands of men. Merry, still wounded, stays in Minas Tirith. They reach the Black Gate of Mordor, where the Gatekeeper shows them the coat of Frodo. All seems lost. 

Book VI 

In the meantime Sam, still wearing the Ring, enters the tower of Cirith Ungol, where Frodo is held captive. Sam rescues Frodo and they dress up like Orcs and both escape from the Tower. Frodo gets angry with Sam and demands the Ring back. On their journey to Mount Doom an Orc-company passes by. They have no other choice then to walk in the company. After Sam falls, they can escape from the company. They reach Mount Doom, where Sauron made the Ring. At the top of Mount Doom, with the flames beneath him, Frodo can't part with the Ring. Frodo says in a clear voice "The Ring is mine!". He cannot resist the sinister fascination anymore and is now in its power. At that moment Gollum, who has followed Frodo and Sam, attacks Frodo and bites off the finger on which he is wearing the Ring. Dancing and shouting with joy, Gollum steps too far and falls into the depths. The one great Ring of Power is gone for ever. 
Flames erupt from Mount Doom. The Dark Land of Mordor is shaken to its foundations and scattered to the winds. The Great War is over. 
The two hobbits are brought to Gondor by Gandalf with help of an Eagle. He leads them to King Aragorn. They are treated with the utmost respect by the King and his knights. Aragorn weds Arwen, daughter of Elrond. Aragorn has known Arwen for long. Faramir weds Eowyn and Eomor becomes King of Rohan. After they have recovered, the hobbits are returning to the Shire with Gandalf. On their voyage back they go to Isengard, where Treebeard is restoring everything. He has released Saruman, since he thought that he was harmless. Gandalf fears that Saruman has still got the power of his commanding voice. Gandalf leaves them for a talk with Tom Bombadil. The hobbits return to the Shire. They find it without all recognition. The country has fallen into the power of Saruman. The hobbits decide to rouse the people and they fight a battle at Bywater where they defeat Saruman's men. Frodo defeats Saruman and puts him to a flight. In the end Saruman is knifed in the back by his servant Grima Wormtongue, who is himself killed by the Hobbit's arrows. 
Now the hobbits face the task of restoring law and order in the Shire. It works and with the help of Sam's little box, given to him by the Lady Galadriel, the Shire is again a green country. 
Frodo starts writing a book of his adventures. 
Frodo is not well. The long contact with the evil Ring has made him sick in body and mind. He also suffers from the wound of the Black Riders and the poisoning by Shelob. He knows that he cannot be cured in Middle Earth but must go to the peaceful land of Elves, across the ocean. Therefore he travels to the Grey Havens, where the Elves embark for their own country, leaving the World of Men now that the Third Age has come to an end. Gandalf, too, is leaving Middle Earth where his task is completed. He sails forth into the High Sea and with him Frodo, Bilbo and the Elves. 

What happened after 

Sam marries Rose and becomes Mayor for seven times. After the death of Rose he also travels to the Grey Havens and leaves as the last of the Ring Bearers. 
King Elessar, Aragorn dies and Merry and Pippin lay in the halls of Gondor. After that, Legolas builds a ship and leaves Middle Earth and with him goes Gimli. 

The Title: Sauron once forged twenty rings as instruments of black magic: nine for mortal Men, seven for Dwarves, three for Elves and one, the mightiest of them all, for himself. This One Ring is the Lord of the Rings. The book is about the fate of the Ring. It can be destroyed or be captured by Sauron.