An Unexpected Party and an Unlikely Quest
Bilbo Baggins, a hobbit who loves peace in the Shire, is happy with his easy life at Bag End. One morning, the wizard Gandalf arrives and marks his door. Soon after, thirteen dwarves—Thorin Oakenshield and his group—come for an unexpected party. They explain their plan to travel to the Lonely Mountain to get back their family treasure, stolen long ago by the dragon Smaug. Gandalf, having secretly offered Bilbo as their 'burglar,' convinces a hesitant Bilbo to join. He says they need a fourteenth member for good luck. Despite wanting to stay home, Bilbo is drawn into the adventure and leaves the Shire the next morning with the group.
Trolls, Goblins, and the Discovery of Sting
The journey quickly becomes dangerous. The group meets three unintelligent trolls—William, Bert, and Tom—who capture them. Gandalf tricks the trolls into arguing until morning, turning them to stone. They search the trolls' cave and find swords, including Glamdring and Orcrist for Gandalf and Thorin, and a small elvish dagger for Bilbo, which he names Sting. Later, while hiding in a cave during a thunderstorm in the Misty Mountains, goblins attack them. Bilbo gets separated from the group while escaping. Lost in the dark tunnels, he finds a strange, pale creature named Gollum and a magical ring.
Riddles in the Dark and the Magic Ring
Deep under the Misty Mountains, Bilbo meets Gollum. Gollum, obsessed with his 'Precious' (the Ring), suggests a game of riddles: if Bilbo wins, Gollum will show him the way out; if Gollum wins, he will eat Bilbo. Bilbo, by chance, asks 'What have I got in my pocket?' which Gollum cannot answer. Angry, Gollum goes to get his Ring, but it is gone. Bilbo had picked it up earlier without Gollum knowing. Bilbo realizes the Ring makes him invisible and uses it to follow Gollum to an exit, escaping the goblin tunnels and rejoining the dwarves and Gandalf.
Wargs, Eagles, and Beorn's Hospitality
After escaping the goblins, Wargs (evil wolves) and goblins chase the group near the Wilderland. They hide in trees but are trapped. Gandalf calls the Great Eagles, who save them from danger and carry them to safety near Beorn's home. Beorn, a skin-changer who can turn into a bear, is careful at first. After Gandalf tells him their story (introducing the dwarves in small groups), Beorn offers them a place to stay, supplies, and ponies for their trip through Mirkwood Forest. He warns them not to leave the path.
Lost in Mirkwood and the Spiders' Web
Gandalf leaves the group at Mirkwood's entrance, reminding them of Beorn's warning to stay on the path and avoid the enchanted stream. The journey through the dark, heavy forest is long and hard. Hungry and curious, and ignoring Beorn's and Gandalf's warnings, Bombur falls into the enchanted stream and goes into a deep sleep. Later, they see lights far away, leave the path many times to look, and are caught by giant spiders. Bilbo, using Sting and the Ring's invisibility, bravely fights off the spiders, saving the dwarves and showing his skill as a burglar and a hero.
Elvenking's Dungeon and Barrel Escape
Soon after escaping the spiders, Wood-elves, led by the Elvenking, capture the dwarves. Thorin, refusing to tell his quest, is jailed, and the other dwarves are also locked up. Bilbo, invisible with the Ring, stays free and unseen, exploring the Elvenking's palace for weeks. He learns of a plan to send barrels of wine down the Forest River to Lake-town. Bilbo uses this chance to free the dwarves from their cells and puts each of them into empty wine barrels. He then jumps on the last barrel himself as they are sent into the river, floating toward Lake-town.
Lake-town's Welcome and the Lonely Mountain
The dwarves, bruised but free, arrive in Lake-town, a settlement on the Long Lake, near the Lonely Mountain. The people, descendants of Dale, remember the prophecy of the King Under the Mountain's return and welcome Thorin and his group with great excitement, hoping for the dragon's defeat and renewed prosperity. After resting and celebrating, the group, with supplies and a boat, travels across the lake toward the Lonely Mountain. They eventually find the secret door on the mountain's west side, guided by the moon-letters on Thorin's map.
Smaug's Awakening and the Arkenstone
Following the map's instructions, Bilbo finds the keyhole for the secret door on Durin's Day. The door opens, showing a long passage into the mountain's center. Bilbo, as the chosen burglar, bravely goes inside alone. He finds Smaug sleeping on his large treasure pile. Bilbo successfully steals a big two-handled cup, but Smaug wakes up and immediately notices it is gone. Bilbo makes a second trip, talking with the dragon and looking for weaknesses. He finds a bare spot on Smaug's underside. Angry about the intrusion and Bilbo's disrespect, Smaug bursts from the mountain and flies to destroy Lake-town.
The Death of Smaug and the Battle of Five Armies
Smaug attacks Lake-town, bringing fire and destruction. The people fight back bravely, led by Bard, a serious archer and descendant of Girion, Lord of Dale. A thrush, having heard Bilbo's talk with Smaug, tells Bard about the dragon's weak spot. Bard, using his family's black arrow, shoots Smaug directly in the unarmored spot, killing the dragon as it falls into the Long Lake. With Smaug dead, the dwarves reclaim the mountain. However, news of the treasure attracts the Men of Lake-town and the Elves of Mirkwood, who demand a share. Thorin, consumed by dragon-sickness, refuses. This leads to a standoff and the Battle of Five Armies against invading goblins and Wargs.
The Arkenstone's Role and Thorin's Redemption
Before Smaug's death, Bilbo had found the Arkenstone, the greatest treasure of Thorin's family, and kept it hidden. To stop war between the dwarves, men, and elves, Bilbo secretly gives the Arkenstone to Bard and the Elvenking, hoping to use it to get Thorin to talk. Thorin is very angry when he learns of Bilbo's 'betrayal' and offers to trade Bilbo's share of the treasure for the Arkenstone. Just as war seems sure, Gandalf reveals that Goblins and Wargs are coming, uniting the different groups against a common enemy in the Battle of Five Armies. Thorin, despite his earlier greed, fights well but is badly wounded.
Aftermath and the Journey Home
The Battle of Five Armies is won, but with many losses. Thorin Oakenshield, fatally wounded, makes peace with Bilbo before he dies, recognizing Bilbo's courage and wisdom. Fili and Kili also die. Dain Ironfoot becomes the new King Under the Mountain. The treasure is divided, with some going to the Men of Lake-town and the Elves. Bilbo gets his share, though he gives up most of it. He travels back to the Shire with Gandalf and Beorn, a much wealthier, wiser, and more experienced hobbit. He arrives home to find his belongings being auctioned, as he was presumed dead, but he reclaims his hobbit-hole and settles into a life that is forever changed.