Eragon, Saphira and the Varden's army have finally captured Belatona, bringing them one step closer to overthrowing Galbatorix.
Unfortunately, Nasuada, the leader of the Varden, is kidnapped by the evil king's bound servant, Murtagh. Eragon remembers advice Solembum had given him when the two first met, about a weapon and the Rock of Kuthian. He sets off to search for the hidden weapon.
The first of Solembum's predictions, the weapon under the Menoa tree, was a special kind of metal that could not be broken by normal means. He forged this into a sword. He proceeded to travel to the Rock of Kuthian.
Meanwhile, Nasuada is being held captive by King Galbatorix. She is given the option to surrender, but Nasuada pushes through Galbatorix's manipulation. She grows weaker each day from frequent beatings and lack of food. Murtagh feels sorry for her and casts a spell to dull the pain of her wounds. He often comes to keep her company and to talk with her.
Eragon finally arrives at the island that was said to house the Rock of Kuthian. He, Saphira and Glaedr must concentrate on discovering their true names to gain access to the Vault of Souls under the Rock.
All three correctly guess their true names, but only Eragon was able to open the Vault of Souls. The trio entered the cave and proceeded to make their way to the end. Eragon was met with a surprise. Hundreds of dragon eggs and Eldunari sat in hollowed pockets of the wall, waiting for the next Rider to use them in the quest of killing Galbatorix.