Riding the dragon off its true course

Adapting movies from popular books for youths is always a dangerous proposition as filmmakers struggle to appease passionate readers and at the same time appeal to a broader audience. Last year’s holiday hits “The Chronicles of Narnia: The Lion, the Witch and the Wardrobe” and “Harry Potter and the Goblet of Fire” prove the feat can be accomplished, but then there are movies such as the fantasy tale “Eragon,” which takes an already derivative plot and guts it like so many Urgals.

Based on the bestselling 2003 novel written by then-teenager Christopher Paolini, “Eragon” is at its core “Star Wars” grafted into Middle-earth. Newcomer Ed Speleers plays Eragon, a coming-of-age farmboy raised by his Uncle Garrow (Alun Armstrong).

After Garrow’s death, Eragon is taken under the wing of Obi-Wanish Brom (Jeremy Irons), who tutors him in magic and warfare as they travel to join the rebellious Varden and their fight against the evil Empire.

The twist to the theme is that Eragon discovers a dragon egg, and when it hatches he’s literally marked as one of the mythical dragon riders a la the Jedi knights. The dragon, who communicates telepathically with Eragon via the maternal voice of Rachel Weisz, manages to age from near infancy to young adulthood during a single flight.

Screenwriter Peter Buchman similarly truncates the rest of the source material and in so doing fails to adequately develop the relationship between Eragon and his dragon and renders key characters superfluous, such as the charismatic and mysterious Murtagh (Garrett Hedlund, a potentially better choice for Eragon over the ultra-vanilla Speleers). In contrast, an Elven warrior (played luminously by Sienna Guillory) receives extra screen time as eye candy decked out in a single-shoulder bodice and later in body-hugging armor akin to a cheung-sam.

Inevitably, “Eragon” reaches its less-than-epic final battle between the Varden and the Urgals, who despite their monstrous name are disappointingly human. It’s here that first-time director and Industrial Light & Magic veteran Stefen Fangmeier finally gets to flex his muscles, but again it’s at the expense of the original material as he replaces the book’s climactic scene with a dizzying aerial battle featuring Eragon and his dragon against a sorcerer Shade (Robert Carlyle) astride a giant bat.

Given Weta Digital’s involvement in “Eragon,” comparisons to the “Lord of the Rings” trilogy are unavoidable. Such talk would be high praise indeed; unfortunately, any conversation involving “Eragon” is likely to center on its place among the likes of “Dragonheart,” “Reign of Fire” and the rest of the mediocre dragon flicks.

MPAA rating: PG for fantasy violence, intense battle sequences and some frightening images. Running time: 1 hour, 39 minutes. In general release.