Game description from the publisher:
Journey to Lonely Mountain for a showdown with the biggest, baddest fantasy dragon of them all — SMAUG! Along the way you'll face giant spiders, malicious elves, suspicious humans, and the most epic barrel-ride ever! The Hobbit: The Desolation of Smaug Deck-Building Game Expansion Pack continues the journey players began in An Unexpected Journey by adding a second main deck and a fire-breathing dragon!
When the final Archenemy of An Unexpected Journey is defeated, this new main deck and the Archenemy Smaug swoop in to continue the story. The new main deck contains none of the lower-cost cards that the first set does as the game and your deck will have progressed to all-new heights.
When you have amassed enough Power, you can take on Smaug! Taunt and flatter Smaug long enough and you might find a chest of gems, a golden goblet, or even the Arkenstone! In the end, the player who has accumulated the most Victory Points from the cards in his deck wins.
Cryptozoic's The Lord of the Rings/The Hobbit deck-builder series:
The Lord of the Rings: The Fellowship of the Ring Deck-Building Game
The Lord of the Rings: The Two Towers Deck-Building Game
The Lord of the Rings: The Return of the King Deck-Building Game
The Hobbit: An Unexpected Journey Deck-Building Game
The Hobbit: The Desolation of Smaug Deck-Building Game Expansion Pack