Since The Hobbit is a substantial novel, here is a concise summary of the epic journey from Bag End to the Lonely Mountain.
The Unexpected Party
Bilbo Baggins, a comfort-loving Hobbit, is visited by the wizard Gandalf the Grey. Gandalf recruits him to be a "burglar" for a company of thirteen Dwarves, led by Thorin Oakenshield. Their goal is to reclaim their ancestral home, the Lonely Mountain, and its massive treasure from the dragon Smaug.
The Journey Begins
The group travels through the Wild, narrowly escaping several dangers:
The Trolls: Bilbo and the Dwarves are almost eaten by three trolls, but Gandalf tricks them into staying out until dawn, which turns them to stone.
Rivendell: They rest with Elrond and the Elves, who help them translate ancient "moon-letters" on their map.
The Misty Mountains: During a storm, they are captured by Goblins. Gandalf rescues them, but Bilbo becomes separated from the group.
Riddles in the Dark
Lost in the goblin tunnels, Bilbo finds a gold ring on the ground. He encounters a creature named Gollum. They engage in a high-stakes riddle contest; if Bilbo wins, Gollum shows him the way out; if he loses, Gollum eats him. Bilbo wins by asking, "What have I got in my pocket?" He discovers the ring makes him invisible, allowing him to escape Gollum and rejoin the Dwarves.
Into the Mirkwood
After escaping Wargs (giant wolves) with the help of Great Eagles and staying with the skin-changer Beorn, the group enters the dark forest of Mirkwood.
Spiders: Bilbo saves the Dwarves from giant spiders using his sword (which he names Sting) and his ring.
Wood-elves: The Dwarves are captured by the Elvenking, Thranduil. Bilbo remains invisible, steals keys, and sneaks the Dwarves out inside empty wine barrels floating down the river.
The Dragon and the Mountain
They arrive at Lake-town and eventually reach the Lonely Mountain. Bilbo sneaks into the lair and talks to Smaug. He notices a small bare patch on the dragon's armored chest.
Enraged by the theft of a golden cup, Smaug attacks Lake-town. However, a brave archer named Bard learns of the dragon's weakness from a thrush and kills Smaug with a Black Arrow.
The Battle of the Five Armies
With the dragon dead, the people of Lake-town and the Wood-elves demand a share of the treasure to rebuild. Thorin, consumed by "dragon-sickness" (greed), refuses and calls for his kinsman Dáin to bring an army.
To prevent war, Bilbo steals the Arkenstone (the most precious gem) and gives it to Bard and Thranduil as a bargaining chip. Thorin is furious, but before a fight breaks out, a massive army of Goblins and Wargs arrives. This forces the Elves, Men, and Dwarves to unite.
The Battle Results:
The Eagles and Beorn arrive to turn the tide.
The Goblins are defeated.
Thorin is mortally wounded. Before he dies, he reconciles with Bilbo, telling him the world would be merrier if more people valued food and cheer above hoarded gold.
The Return Home
Bilbo returns to the Shire with a small portion of the treasure. He finds that his neighbors thought he was dead and were auctioning off his belongings. Though he is no longer considered "respectable" by other Hobbits, he is happy, wise, and content with his memories and his secret ring.
How do you feel about Thorin's change of heart at the end of the story?