The dwarves, along with Bilbo Baggins and Gandalf the Grey, continue their quest to reclaim Erebor, their homeland, from Smaug. Bilbo Baggins is in possession of a mysterious and magical ring.
Hiccup (Jay Baruchel) is a Norse teenager from the island of Berk, where fighting dragons is a way of life. His progressive views and weird sense of humor make him a misfit, despite the fact that his father (Gerard Butler) is chief of the clan. Tossed into dragon-fighting school, he endeavors to prove himself as a true Viking, but when he befriends an injured dragon he names Toothless, he has the chance to plot a new course for his people's future.
Eragon (Ed Speleers), a poor farm boy, lives in Alagaesia, a kingdom ruled by Galbatorix (John Malkovich), a powerful but evil monarch. One day, Eragon discovers a beautiful stone that he soon realizes is a dragon's egg. When the creature hatches, Eragon sets forth on a path that could restore the glory of his homeland's legendary Dragon Riders and perhaps overthrow Galbatorix.
A knight returning from the Crusades takes on a dragon and becomes a legend.
A brood of fire-breathing dragons emerges from the earth and begins setting fire to everything, establishing dominance over the planet.
The last dragon and a disillusioned dragonslaying knight must cooperate to stop an evil king who was given partial immortality.