The Hobbit: An Unexpected Journey (2012) Official Synopsis

Here's the full press release which is full of a bunch of other details:

From Academy Award®-winning filmmaker Peter Jackson comes The Hobbit: An Unexpected Journey, the first of two films adapting the enduringly popular masterpiece The Hobbit, by J.R.R. Tolkien. The second film will be The Hobbit: There and Back Again.

Both films are set in Middle-earth 60 years before The Lord of the Rings, which Jackson and his filmmaking team brought to the big screen in the blockbuster trilogy that culminated with the Oscar®-winning The Lord of the Rings: The Return of the King.

The adventure follows the journey of title character Bilbo Baggins, who is swept into an epic quest to reclaim the lost Dwarf Kingdom of Erebor from the fearsome dragon Smaug. Approached out of the blue by the wizard Gandalf the Grey, Bilbo finds himself joining a company of thirteen dwarves led by the legendary warrior, Thorin Oakenshield. Their journey will take them into the Wild; through treacherous lands swarming with Goblins and Orcs, deadly Wargs and Giant Spiders, Shapeshifters and Sorcerers.

Although their goal lies to the East and the wastelands of the Lonely Mountain first they must escape the goblin tunnels, where Bilbo meets the creature that will change his life forever…Gollum.

Here, alone with Gollum, on the shores of an underground lake, the unassuming Bilbo Baggins not only discovers depths of guile and courage that surprise even him, he also gains possession of Gollum’s “precious” ring that holds unexpected and useful qualities … A simple, gold ring that is tied to the fate of all Middle-earth in ways Bilbo cannot begin to know.