In the fantastical land of something or other, a restless, blandly cute teenager (Edward Speleers) comes into possession of an oversized, metallic piece of Good & Plenty candy, which turns out to contain a baby dragon and the lad’s destiny. Devotees of Christopher Paolini’s best seller surely will find plenty to complain about, but the film version, adapted by Jurassic Park III screenwriter Peter Buchman for visual-effects journeyman and first-time director Stefen Fangmeier, is faithful in the sense of seeming to have been conceived by a 15-year-old. And in general it’s about as by-the-book as a movie about a boy and his dragon can be. This boy and his dragon (voiced by Rachel Weisz) must battle some sort of militaristic screamo-band frontman (Robert Carlyle) to save the land from the tyranny of an evil king (John Malkovich). With no shortage of swords, sorcery, Star Wars rip-offs or syrup-thick narration, Eragon is diligently overdone by all involved, not least the silence-averse composer Patrick Doyle. What does it say that Jeremy Irons is the least self-serious performer in the cast?