Eragon, a young adult fantasy novel, is the first book in the Inheritance Cycle. It tells the story of a young boy named Eragon who hatches a dragon, Saphira, out of a mysterious stone he finds in the woods. Eragon bonds closely with Saphira and becomes a dragon rider, drawing the attention of the evil king Galbatorix, who sends his servants, the Ra'zac, to kill him. While escaping from the Ra'zac, Eragon and his mentor Brom become embroiled in plots against the evil king.
Woken by a dwarf summoning him to see Ajihad, Eragon soon learns that an army of Urgals is on its way to Tronjheim, using the tunnels to arrive underneath the mountain. They could not have known of the invasion because of the amount of tunnels that exist and have not been used for years. They are going to collapse tunnels to stall the Urgals and keep them from running loose in the city. Arya and Eragon are given the task with their magic. They must keep the Urgal in Farthen Dûr, away from the majority of the dwarves and refugees.
Eragon uses his magic to find weak spots and collapse the tunnels, but the work is exhausting. As he prepares for battle, Hrothgar gifts him with dragon armor for Saphira and Orik give him chain mail for himself. Elsewhere, warriors prepare hot pitch to pour down other tunnels to kill the Urgal. Murtagh arrives as well, fully dressed and ready for battle. Ajihad asks Eragon to keep in touch with the Twins and to minimize his risks during battle as they need him as a Dragon Rider. Arya arrives as well, ready for battle, explaining that Elven women are trained as much as the men for battle. They must wait through the night for the battle to begin.