When the first book in the trilogy opens, Eragon is just a farm boy from a remote valley; when he discovers a dragon egg and it hatches, he and the dragon, Saphira, become linked for life and he assumes the only person alive with the rare and powerful status of a Dragon Rider. He and Saphira are pursued by the king, Galbatorix, a Dragon Rider himself who became evil; Galbatorix’s sinister, inhuman agents kill his Uncle Garrow, who raised him, and burn his farm. Eragon flees with the village storyteller, Brom, who turns out to be a former Dragon Rider himself; Brom instructs Eragon in some of what he needs to know, and eventually dies defending him. A series of other adventures leads Eragon and Saphira to Farthen Dûr, a hollow mountain that contains both a dwarf city where the human resistance fighters, the Varden, make their temporary home. Durza, a powerful Shade in Galbatorix’s service, leads an army of the monstrous, warlike Urgals to attack Farthen Dûr; with the help of Saphira, an elf named Arya, a mysterious dream-presence who calls himself The Cripple Who Is Whole, and good luck, Eragon manages to kill Durza, though he sustains a terrible wound across his back in the process.
Eldest opens in the aftermath of this battle. Eragon realizes that he needs to learn more and decides to take the advice of The Cripple Who Is Whole and go to the land of the elves in order to study magic and fighting. Stability among the Varden is threatened when the leader of the group is killed in a follow-up Urgal-tracking operation; Eragon’s friend Murtagh and a pair of sorcerers named the Twins disappear in the same operation. The Varden choose their fallen leader’s daughter, Nasuada, to lead them; Eragon and Saphira, as important public figures, are asked to endorse this choice, which they do. Before they leave the land of thedwarves, the dwarf king asks to adopt Eragon as an honorary member of his family. Nasuada decides to move the Varden to the free land of Surda to organize another strike against Galbatorix.
Meanwhile, Eragon’s cousin, Roran, returns to their home village of Carvahall hoping to marry the butcher’s daughter, Katrina. The village is besieged by imperial soldiers, led by Galbatorix’s sinister agents, the Ra’zac, who are looking for Roran. The villagers begin resisting; they fight well, but their opponents are more powerful and vow to destroy the villagers. When the Ra’zac capture Katrina, Roran organizes his community to travel en masse to Surda to join the resistance, a journey that is completed only with many hardships, and which changes Roran into a toughened, sometimes ruthless leader.
Eragon, Saphira, Arya, and a dwarf named Orik travel to Ellesméra, the capital city of the elves, which is buried deep in a forest, for further training. There the elves reveal to him The Cripple Who Is Whole, an elderly Dragon Rider; he and his dragon can no longer fight, but they instruct Eragon and Saphira. Eragon becomes a very powerful magician and fighter and, in a ritual celebrating the origin of the Riders, a mysterious dragon magic alters his form so that he takes on the strength and appearance of an elf rather than a person. Meanwhile, he falls in love with Arya, who rebuffs his many advances; the match would be impossible, because she is overa hundred years old and an elf princess.
Finally, Eragon and Saphira realize through magical means that Galbatorix’s army is massing for a major attack and go to join the Varden and the people of Surda in the battle. Roran and the villagers arrive via a stolen boat, and Roran makes an important contribution to the battle. Eragon fights mightily, but at a crucial moment another rider appears; one of the two eggs in Galbatorix’s position hatched and Murtagh, who was captured from Farthen Dûr because of the treachery of the Twins, has become a Dragon Rider sworn to do Galbatorix’s will. As he fights his former friend, Murtagh reveals to Eragon that they are brothers; Murtagh’s father, a treacherousRider who betrayed the order to follow Galbatorix, is also Eragon’s unknown parent. Murtagh’s magic is more powerful than Eragon’s, but he lets Eragon escape. Eragon and Roran are reunited and decide to call each other brother and attempt to rescue Katrina and kill the Ra’zac.