The Clouds Burst
The Clouds Burst is the 17th chapter of The Hobbit.
Thranduil, Bard, and Gandalf pleaded with Thorin to share the wealth of Erebor with the people of Middle-earth. They revealed themselves to be in possession of the Arkenstone, which was previously stolen and given to them by Bilbo. Thorin reluctantly agrees to part with one-fourteenth of his treasure in trade for the Arkenstone, although he raged against Bilbo and cast him from Erebor in anger, their friendship apparently broken. In preparation for the upcoming battle, the sturdy, mattock-wielding Dwarves of Dáin Ironfoot came as reinforcements. Tensions ran high as Dáin's Dwarves sought to reach the Mountain, while archers and spearmen under Bard barred their approach. Conflict began between the Elves and Dwarves, even as a black cloud gathered and the Goblin army under Bolg arrived.
Thus began the Battle of Five Armies, between the Goblins and Wolves, and the Elves, Men, and Dwarves. The reader learns that the Goblins had been amassing in the wake of the Great Goblin's death, and had set themselves on capturing the Lonely Mountain. A strategy had arisen: the goblins would be lured into the valley between the arms of the Mountain, and there be cornered and destroyed. Bilbo wore the magic ring to utilise its powers of invisibility. The Elves charged first in wrath, and killed countless Orcs. Then the dwarves under Dáin attacked, routing the enemy and striking panic into the orcs. Victory seemed to be at hand, when the forces of good were ambushed by Orcs, scaling the Mountain.
Battle raged on, with Bard defending the Eastern spur of the mountain, and the Elves fighting on Ravenhill. Thorin and the Company of dwarves burst out of the mountain in battle armor, rallying morale. Calling all elves, dwarves, and men alike to him, Thorin rallied the armies on a counter-attack against the orcs. Thorin attempted to break the bodyguard of Bolg, composed of goblins of huge size, but no progress was reached, and the tide of battle began to change. The armies of men, elves, and dwarves found that their efforts were in vain, as the countless numbers of orcs and ceaseless onslaught rendered their efforts futile.
Bilbo, fighting on Ravenhill with the elves, cried in disdain as defeat became apparent. He regretted the death and ruin caused by plundering of the golden hoard of Smaug. Then out of the sky, the majestic Eagles swooped down in great numbers, prompting Bilbo to cry "The Eagles! the Eagles!" in great joy. Bilbo was then struck by a hurled stone, and went unconscious.