Thorin and his company are being pursued by Azog and his Orc party following the events of the previous film. They are ushered along by Gandalf to the nearby home of Beorn, a skin-changer who can take the form of a bear. That night, Azog is summoned to Dol Guldur by the Necromancer, who commands him to marshal his forces for war. Azog then delegates the hunt for Thorin to his son Bolg. The following day, Beorn escorts the company to the borders of Mirkwood, where Gandalf discovers Black Speech imprinted on an old ruin. This coincides with a telepathic message from Galadriel urging him to investigate the tombs of the Nazgûl. He warns the company to remain on the path and leaves them. Upon entering the forest they lose their way and are ensnared by giant spiders. Bilbo then sets about freeing the dwarves with the help of his recently acquired invisibility ring. He subsequently drops the Ring and first begins to understand its dark influence after he brutally kills a creature to retrieve it.
The remaining spiders are fended off by the Wood-elves led by Tauriel and Legolas. They also capture the Dwarves and bring Thorin before their king Thranduil. Thorin confronts the Elvenking about his neglect of the Dwarves of Erebor following Smaug's attack 170 years earlier and is consequently imprisoned with the other Dwarves. Bilbo, having avoided capture, arranges an escape using empty wine barrels that are sent downstream. While being pursued by the Wood-elves, they are ambushed by Bolg and his Orc party, and Kíli is wounded with a Morgul shaft. They engage in a running three-way battle down the river, but ultimately the Dwarves are able to escape both groups of pursuers. Thranduil then seals off his kingdom when an Orc captive reveals an evil entity has returned and is amassing an army in the south, but Tauriel decides to leave and assist the Dwarves; Legolas goes after her. Meanwhile, Gandalf and Radagast go to investigate the tombs of the Nazgûl, which they find to be empty.
The company is smuggled into Esgaroth by a bargeman called Bard. Thorin promises the Master and the people of Laketown a share of the mountain's treasure. It is then revealed that Bard is a descendant of the last ruler of Dale, and possesses the last black arrow capable of killing Smaug. Kíli is forced to remain behind, tended to by Fíli, Óin, and Bofur, as the remaining company receives a grand farewell. Meanwhile, Gandalf travels south to the ruins of Dol Guldur, while Radagast leaves to warn Galadriel of their discovery at the tombs of the Nazgûl. Gandalf finds the ruins infested with Orcs and is ambushed by Azog. The Necromancer overpowers and defeats Gandalf and reveals himself as Sauron.
Thorin and his remaining company reach the Lonely Mountain, where Bilbo discovers the hidden entrance. He is sent in to retrieve the Arkenstone, and while doing so, he accidentally awakens Smaug. While conversing with Bilbo, Smaug reveals his knowledge of both the dwarves' plot to retake the gold and the return of Sauron. Back in Laketown, Bard attempts to bring the black arrow to the town's launcher, as he fears what may happen when the Dwarves enter the mountain. However, he is arrested by the Master and his conniving servant, Alfrid, in the process and leaves his son to hide the arrow. Bolg and his Orc party then infiltrate the town and attack the four Dwarves, but are quickly dispatched following the arrival of Tauriel and Legolas; Tauriel then tends to Kíli. While Kíli is recovering, he openly admires Tauriel's beauty and wonders if she loves him. Legolas leaves in pursuit of Bolg. Meanwhile, Gandalf watches helplessly as Azog and an Orc army march from Dol Guldur towards the Lonely Mountain.
Back inside the mountain, during a long chase, Bilbo and the Dwarves rekindle the mountain's forge using Smaug's flames to create and melt a large golden statue, hoping to bury Smaug alive in the molten gold. They do so, but Smaug emerges from the gold, stumbles out of the mountain and flies off to destroy Laketown as Bilbo watches after him in horror and despair.
Martin Freeman as Bilbo Baggins
Ian McKellen as Gandalf the Grey: An Istari wizard
Richard Armitage as Thorin Oakenshield II: The leader of the Company of dwarves and the true heir to Erebor's throne
Benedict Cumberbatch as Smaug (vocal performance/motion capture): An enormous, powerful and psychopathic great dragon of Middle-earth who claimed the Lonely Mountain, its vast treasures and the surrounding human areas.
Cumberbatch also plays Necromancer: A mysterious sorcerer residing in Dol Guldur
Evangeline Lilly as Tauriel: The elven chief of the Mirkwood Guards serving under Thranduil,
Luke Evans as Bard the Bowman: A skilled archer living in Esgaroth and the heir of Girion, the last king of old Dale. Evans also plays Bard's ancestor, Girion, in a flashback.
Lee Pace as Thranduil: The aloof and cold-hearted Elven king of the northern part of Mirkwood (the Woodland Realm).[12][13]
Stephen Fry as Master of Lake-town: The pompous and greedy mayor of the settlement of Men at Lake-town near the Lonely Mountain
Orlando Bloom as Legolas Greenleaf: An elf from Mirkwood and the prince of the Woodland Realm - he is Thranduil's son.
Graham McTavish as Dwalin: Balin's brother.
Ken Stott as Balin: Dwalin's brother.
Aidan Turner as Kíli: One of Thorin's nephews and Fili's younger brother.
Dean O'Gorman as Fíli: Another of Thorin's nephews and Kili's older brother.
Mark Hadlow as Dori: Nori and Ori's brother.
Jed Brophy as Nori: Dori and Ori's brother.
Adam Brown as Ori: Dori and Nori's brother.
John Callen as Óin: Glóin's brother.
Peter Hambleton as Glóin: Óin's brother and father of Gimli
William Kircher as Bifur: Bofur and Bombur's cousin.
James Nesbitt as Bofur: Bombur's brother and Bifur's cousin.
Stephen Hunter as Bombur: Bofur's brother and Bifur's cousin.
Cate Blanchett as Galadriel
Mikael Persbrandt as Beorn
Sylvester McCoy as Radagast the Brown
Manu Bennett as Azog the Defiler
Lawrence Makoare as Bolg: Son of Azog the Defiler.
Craig Hall as Galion: Thranduil's butler
Ryan Gage as Alfrid: The Master of Laketown's conniving and arrogant servant.
John Bell as Bain: Bard's son
Mark Mitchinson as Braga: captain of the Lake-town Guard.
Ben Mitchell as Narzug
Stephen Ure as Fimbul, Azog's second-in-command
Robin Kerr as Elros: An elf of the Woodland Realm
Simon London as Feren: An elf of the Woodland Realm.
Dallas Barnett as Bill Ferny Snr
the second installment in the three-part film series based on the novel The Hobbit by J. R. R. Tolkien. The film was preceded by An Unexpected Journey (2012) and followed by The Battle of the Five Armies (2014); together they operate as a prequel to Jackson's The Lord of the Rings film trilogy.