The subject of this article originates from non-canonical sources. To find out about what is considered "canon" see LOTR:Canon.
In TA 2941, Thorin II Oakenshield led his company of dwarves across the path of Mirkwood in order to reach the Lonely Mountain and reclaim their homeland from the dragon Smaug, who took over the mountain for many years. However, the company started to succumb to the sickness, which infected the entire forest, and would eventually be captured by a group of Giant Spiders that spawned from the old fortress of Dol Guldur, the place where the Dark Lord Sauron (nicknamed the Necromancer) lingered and was preparing send forth his legions to attack the mountain. Bilbo Baggins, the company's burglar, was the first to escape after slaying a spider and used the magical ring (that he found in Gollum's cave) to make him invisible and free his companions.
After freeing the dwarves, Bilbo attempted to unite with them until he got himself separated when dozens of spiders were crawling towards the company. While the dwarves were trying to make their escape, Legolas, son of Thranduil, and group of Silvan Elves of Mirkwood surrounded them and prevented their escape. The dwarves were brought to King Thranduil, who ordered his guards to lock the dwarves in the dungeon while he attempts to make a deal with Thorin. Thorin refused to accept Thranduil's deal since he never forgot the time when the Elven King turned his back on him and his people after the dragon took over Erebor.
In the morning, Bilbo Baggins managed to free his companions when he still used the magical ring to keep himself invisible and stole the keys from the wine cellars. Together, they manage to escape through the halls of Thrandruil through barrels thrown into the river. Unfortunately, the Elves discover this trick and managed to prevent them from escaping. Before the elves attempted to arrest the dwarves, Bolg led a large group of 200 Orcs to attack the company and the elves. The dwarves were weaponless, but they managed to fight off the orcs and steal a couple of their weapons while Kili attempted to open the gate.
Before Kili reached the lever, Bolg shot a Morgul arrow straight into the dwarf's leg, preventing him from opening the gate of the river. That was when Tauriel arrived and managed to save Kili by shooting several orcs while Legolas and the rest of the elves arrive to engage the orcs. As the fighting progressed, Kili managed to open the gate and escape with the dwarves across the long river run. Bolg leads the orcs after the dwarves, but Legolas, Tauriel, and the Elves give pursuit and fight them in order to recapture Thorin and Company. After the dwarves managed to escape and make their way to the Long Lake, Tauriel saves Legolas from Narzug, who was close to killing the prince. Before she could kill Narzug, Legolas told her that they would keep him alive and interrogate him.
Inside the Halls of the Woodland Realm, Legolas, Tauriel, and Thranduil interrogate Narzug, who refuses to talk. When the Elven King promised the orc that he would set him free, Narzug reveals "His Master" serves the "One" and that the world "will burn in the flames of war". After getting all the information, Thranduil beheaded Narzug with his sword.
- The Hobbit: The Desolation of Smaug (First appearance)