The lasting mystery of "The Spiderwick Chronicles" is why the producers cast actors known for rising to a creative challenge - and then gave them so little to do. Mary-Louise Parker, David Strathairn, Nick Nolte, Dame Joan Plowright - Laurence Olivier's widow, for Pete's sake - all rattle around this noisy action-fantasy contraption looking vaguely stunned. And why shouldn't they? The movie's tweenage target audience has no idea who they are.
Freddie Highmore gets to play twins, though, and that's something. Produced by Nickelodeon and based on a popular book series by Tony DiTerlizzi and Holly Black, "Spiderwick" occupies a niche between one of the lower-rent Walden Media young-adult-lit adaptations and "The Chronicles of Narnia" - it's "The Golden Compass" shrunk down to the size of a few cubic acres.
On those acres stands a creepy old house, and into that house move the Graces: newly separated mom (Parker), twins Jared (Highmore) and Simon (Highmore), and teenage daughter Mallory (Sarah Bolger, one of the sisters in "In America"). Jared is bitter - he doesn't know that dad (a briefly glimpsed Andrew McCarthy) is a cheating rat - and he sulks his way into a hidden study where ancestor Arthur Spiderwick (Strathairn) carried out his studies on the faerie realm.
Yes, faeries are real - and brownies and boggarts and sylphs and goblins - and "Spiderwick Chronicles" visualizes them all with duly detailed digitized wonder. Martin Short provides the voice of Thimbletack, a honey-loving house brownie who turns green and bulbous when angered, and there's a piggy hobgoblin who speaks with the frathouse swagger of Seth Rogen.
Great Uncle Arthur wrote a book about the faeries, though, and "Spiderwick" being that sort of movie, it's a book that will Bring About the End of the World if it falls into the hands of Mulgarath, a shapeshifting ogre with the voice and occasionally the makeup-larded face of Nolte. Two-thirds of the film consists of the panicked kids fighting off the bellowing forces of evil just outside the house, trying to hide the apocalypse from mom.
It's a good movie for its type, but it rarely stops to let us marvel at the world it creates. (It's also an assault of noise, action violence, and slimy-creature effects that will delight kids older than eight and terrify their younger siblings - you've been warned.) When the kids visit Uncle Arthur's daughter, the aged Lucinda (Plowright), we do glimpse some remarkable flower-faeries that could have stepped out of "Fantasia" - they're as graceful as the actress herself. More typical are the howling goblins hordes: meticulously rendered hellbeasts that look like Hieronymus Bosch's idea of a Surinam toad.
The most special effect is probably Highmore, who gets to sharpen up his American accent and who makes each twin, bookish Simon and bad-boy Jared, a functioning individual. In its way, "The Spiderwick Chronicles" is a ripsnorting, computerized update of E. Nesbit's old fantasy novels for children, and the way brothers and sister band together to deal with the unknown is reminiscent of Nesbit's far gentler and funnier "Five Children and It." Maybe Nickelodeon should make that one next, and let Highmore play all the roles.