You've heard of Young Indiana Jones--now meet Young James Bond. This much-trumpeted Brit actioner tells the story of a teenage boy who's unexpectedly given a job with MI6, Britain's equivalent of the CIA. It's a moderately enjoyable affair which only drags in the middle, where an excess of plotting overshadows the characters. The movie has been faithfully adapted from the best-selling Alex Rider book series by its author, Anthony Horowitz.

Released here under a Weinstein Company banner, Alex Rider: Operation Stormbreaker lacks the star power to hit big in the U.S. Ewan McGregor only appears in a short--albeit action-packed--prologue, and it's unlikely whether a dishevelled Mickey Rourke will appeal much to a PG audience. Alicia Silverstone garners screen time in a supporting role, but it's left to first-timer Alex Pettyfer and a host of Brit character actors to carry the show. Marketing-wise, the best bet would be to sneak it out as a Brit variation on Spy Kids, while harping on about the similarities with James Bond.

Directed by Britain's Geoffrey Sax, who cut his teeth in TV productions, Operation Stormbreaker starts out with a neat and fun set-up. Alex (Pettyfer) is a middle-class school kid who's disappointed that his businessman uncle Ian (McGregor) never has time for him. When Ian is murdered by an Eastern European bandit, Alex realises that something's up. Some moseying around leads to the discovery that his uncle was actually a top spy who had been secretly training him as his successor-those rock-climbing trips and language courses weren't just for fun. To the disappointment of his nanny (Silverstone), Alex takes over his uncle's job at MI6 and tries to track down his killers.

From then on, action takes precedence over story, and Alex takes on numerous villains under the control of evil computer supremo Darrius Sayle (Rourke). Best of these is Teutonic nutcase Nadia Vole (Missi Pyle), who's a dead ringer for Bond nemesis Elsa Klebb. The plot hinges-very erratically-around a virtual-reality machine that Sayle has built to release deadly chemicals into the atmosphere. The denouement sees Alex rushing to save the British Prime Minister (Robbie Coltrane) from a showdown with the villains.

The first act is neat enough, but as the story takes off, the film becomes overloaded. The portly Rourke, who's vaguely attempting to channel Orson Welles in Touch of Evil, is well-cast, but his villainy is undercut by the presence of the menacing Vole and a murderous Eastern European hit man. There are so many heavies, it's difficult to sustain antipathy towards any of them. The same applies to the heroes-Alex has not one, but two females in his life, and this muddles the arc of the story.

There's also too much running around. An all-inclusive approach means that Alex has to battle everything from Jaws-like henchmen to a giant jellyfish. No action film can afford to allow the audience a dull moment these days, but Hollywood usually demands some scenes of emotional engagement so the audience can sympathize with the character. There are too few of these in Operation Stormbreaker, and viewers won't get as involved as they should have. Still, many of the action scenes work well enough, and a martial-arts fight choreographed by Hong Kong's Donnie Yen is vibrant.

In spite of its predilection for action, the film's appeal comes from its ensemble cast-it's chock-a-block with vignettes from British character actors which are consistently fun. Bill Nighy (Davy Jones in Pirates of the Caribbean: Dead Man's Chest) hams it up as an "M"-like MI6 commander, while Stephen Fry does an appealing take on a "Q"-style gadget genius. Coltrane is a good fit for a fumbling but good-natured Prime Minister. Although American viewers won't be as familiar with these bit players as Brits are, they won't be impermeable to their charm.