A shade named Durza, along with a group of urgals, ambushes a party of three elves. After he and the urgals kill the other elves, Durza attempts to steal a stone that one of the female elves carries, but is foiled when she causes it to vanish. However, he renders her unconscious with a ball of fire and has her at his mercy.
Eragon is a fifteen-year-old boy who has lived with his uncle Garrow and cousin Roran on a farm near the village of Carvahall, ever since his mother, Garrow's sister, left him there right after his birth. While hunting in the Spine, Eragon is surprised to see the blue dragon egg, which he believes to be a stone, appear in front of him. A few months later, Eragon witnesses a baby dragon hatch from the egg. Eragon names the dragon Saphira. He raises the dragon in secret until two of King Galbatorix's servants, the Ra'zac, come to Carvahall, though it is later revealed that they weren't looking for the egg at first. Eragon and Saphira manage to escape by hiding in the Spine, but Garrow is fatally wounded and the house and farm are burned down by the Ra'zac. Once Garrow dies, Eragon is left with no reason to stay in Carvahall, so he goes after the Ra'zac with his newly hatched dragon, seeking vengeance for the destruction of his home and his uncle's death. He is accompanied by Brom, an elderly storyteller, who provides Eragon with the sword Zar'roc and insists on helping him and Saphira.
Eragon becomes a Dragon Rider through his bond with Saphira. Eragon is the only known Rider in Alagaësia other than King Galbatorix, who, with the help of the now-dead Forsworn, a group of thirteen dragon riders loyal to Galbatorix, killed every other Rider a hundred years ago. On the journey, Brom teaches Eragon sword fighting, magic, the ancient elvish language, and the ways of the Dragon Riders. Their travels bring them to the city of Teirm, where they meet with Brom's friend Jeod. Eragon's fortune is told by the witch Angela, and her companion, the werecat Solembum, gives Eragon some mysterious advice. With Jeod's help, they are able to track the Ra'zac to the southern city of Dras-Leona. Although they manage to infiltrate the city, Eragon encounters the Ra'zac in a cathedral and he and Brom are forced to flee. Later that night, their camp is ambushed by the Ra'zac. A stranger named Murtagh rescues them, but Brom is gravely injured. Saphira watches over Brom as the night progresses, yet when morning comes they realize there is nothing they can do to save him. Brom gives Eragon his blessing, reveals that he was also once a dragon rider and that his dragon's name was Saphira, and dies.
Murtagh becomes Eragon's new companion and they travel to the city Gil'ead to find information on how to find the Varden, a group of rebels who want to see the downfall of Galbatorix. While stopping near Gil'ead, Eragon is captured and imprisoned in the same jail that holds a woman he has been having dreams about. As she is being dragged past she is revealed as an elf when her pointed ears are uncovered. Murtagh and Saphira stage a rescue, and Eragon escapes with the unconscious elf. During the escape, Eragon and Murtagh battle with Durza. Murtagh shoots Durza between the eyes with an arrow, and the Shade disappears in a cloud of mist. Then escaping, they run off. Eragon succeeds in communicating with the elf, whose name is revealed as Arya, and learns the location of the Varden. After some arguing, Murtagh decides to still travel with Eragon to the Varden but is still wary of them.
An army of Kull(Urgals who can grow up to 8 feet) reach Eragon right outside the Varden's entrance, but are driven off with the help of the Varden, who escort Eragon, Saphira, Murtagh, and Arya to Farthen Dûr. When they arrive in Farthen Dûr, Eragon is led to the leader of the Varden, Ajihad. Ajihad imprisons Murtagh after he refuses to allow his mind to be read to determine if he is a friend or a foe to the Varden. Eragon is told by Ajihad that Durza was not destroyed by Murtagh's well placed arrow, because the only way to kill a Shade is with a stab through the heart. Orik, nephew of the dwarf King Hrothgar, is appointed as Eragon and Saphira's guide. Orik shows them a place to stay and introduces them to Hrothgar. Eragon also meets Ajihad's daughter, Nasuada, and Ajihad's right-hand man, Jörmundur. He also runs into Angela and Solembum, who have arrived in Tronjheim, and visits Murtagh in his prison. He is tested by two magicians, The Twins, as well as Arya.
He and the Varden are then attacked by the Kull. Eragon personally battles Durza again, and succeeds in stabbing him in the heart with Zar'roc, but at a price. Durza manages to slice a deep cut like Murtagh's on his back. He then passes out, and is visited telepathically by a stranger while he is unconscious who tells Eragon to visit him in the Elven capital, Ellesméra.