A Shade named Durza, along with a group of Urgals, ambushes a party of three elves. They kill two of them, and Durza attempts to steal an egg carried by the remaining female elf. However, she manages to use magic to teleport it elsewhere. Infuriated, Durza abducts her and keeps her prisoner at the city of Gil'ead.
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, left by his mother 15 years before. While hunting, he sees a large explosion and finds a blue dragon egg in the rubble. Later on, a baby dragon hatches from the egg, and bonds with Eragon, giving him a silver mark on his hand. Eragon names the dragon Saphira, after a name the old village storyteller Brom mentions.
He raises the dragon in secret until two of King Galbatorix's servants, the Ra'zac, come to Carvahall. Eragon and Saphira escape and hide in the Spine, but Garrow is fatally wounded and the farm is burned down by the Ra'zac. Once Garrow dies, Eragon and Saphira decide to hunt the Ra'zac, in vengeance. Brom insists on accompanying him and Saphira, and gives Eragon the sword Zar'roc.
Eragon becomes a Dragon Rider, through his bond with Saphira. He is the only known Rider in Alagaësia other than King Galbatorix, who, with the help of the now-dead Forsworn, a group of rogue Riders, killed every other Rider a century ago. As they travel, Brom teaches Eragon sword fighting, magic, the ancient elvish language, and the ways of the Dragon Riders.
They travel 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 mysterious advice. With Jeod's help, they track the Ra'zac to the city of Dras-Leona. They manage to infiltrate the city, but are forced to flee after a run-in with the Ra'zac. That night, they are ambushed by the Ra'zac. A stranger named Murtagh rescues them, but Brom is mortally wounded. Brom gives Eragon his blessing, reveals that he was once a Dragon Rider, with a dragon named Saphira, and dies. Saphira uses magic to encase Brom in a diamond tomb.
Murtagh becomes Eragon's new companion and they travel to the city of Gil'ead, seeking information on how to find the Varden, a group of rebels who seek the downfall of Galbatorix. Near Gil'ead, Eragon is captured and imprisoned in a jail that holds a female elf he had had recurring dreams about. Murtagh and Saphira stage a rescue, and Eragon takes the unconscious elf with him. After fighting Durza, Murtagh seemingly kills him with an arrow shot through his head, and they escape. Eragon telepathically communicates with the elf, named Arya, who reveals she had sent the egg to him accidentally. From her, he learns the location of the Varden. Murtagh is reluctant to journey to the Varden, revealing that he is the son of Morzan, former leader of the Forsworn.
An army of Kull, elite Urgals, chases Eragon to the Varden's headquarters, but is driven off by the Varden, who escort Eragon, Saphira, Murtagh, and Arya to Farthen Dûr, their mountain hideout. Eragon meets the leader of the Varden, Ajihad. Ajihad imprisons Murtagh after he refuses to allow his mind to be read, to determine his allegiance. Eragon is told by Ajihad that Murtagh failed to kill Durza, as 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. Eragon also meets Ajihad's daughter, Nasuada, and Ajihad's right-hand man, Jörmundur. He runs into Angela and Solembum again, and visits Murtagh in prison. He is tested by two magicians, The Twins, as well as Arya.
Eragon and the Varden are then attacked by an immense Urgal army. Eragon personally battles Durza again, and, after a mental battle, is overwhelmed by Durza, who slashes him across the back. Arya and Saphira shatter Isidar Mithrim, a large sapphire that formed the roof of the chamber, to distract Durza, allowing Eragon to stab him through the heart with his sword. He falls into a coma, and is visited telepathically by a stranger, who tells Eragon to visit him in the Elven capital, Ellesméra. He wakes up with a scar across his back, and resolves to journey to Ellesméra.
