Flat-footed when it should be fleet, scary when it means to be exciting, and only intermittently emotionally effective, "The Tale of Despereaux" does a disservice to Kate DiCamillo's well-regarded children's book. Despite a lustrous look that mimics Flemish masterworks and a pedigreed voice cast, this computer-animated fantasy is more ordeal than enchantment. Its heavyhearted aura and lecturing, moralistic tone may fly over the head of young sprouts content to sit mindlessly before the screen, but more sophisticated kids will quickly grow restless.

Matthew Broderick speaks the role of Despereaux, a soft-spoken mouse who scandalizes his peers by openly conversing with humans and reading books rather than gnawing on them. Yes, we are in a fairy world of twee bland mice.

Despereaux lives in the Kingdom of Dor, a mystical place with a soup-based economy whose doleful monarch lives in perpetual gloom. His Queen died in a soup-rodent mishap, and the grieving King has outlawed soup and rats. This rankles the rat Roscuro (Dustin Hoffman), who wants to leave the darkness of sewers and cellars for the light of the streets above.

Meanwhile, Despereaux, lacking the timidity of his fellow mice, forms a friendship with Princess Pea ("Harry Potter's" Emma Watson), a flaxen-haired beauty with the faintly misty, spiritual expression often associated with missing contact lenses. Lumpish chambermaid Miggory Sow (Tracey Ullman) envies the princess' life of luxury. When Despereaux's trespass into the world of humans is discovered, the mice exile him to the dank, virulent rat world, where he is threatened with death by cat before an arena of bloodthirsty cheese-nibblers. Roscuro plots revenge on the King by provoking resentful Miggory to kidnap the princess. Valiant Despereaux must swing from a spool of thread, wield a needle like a swashbuckler and evade snappish mousetraps to save the day. While that may sound like vibrant adventure in summary, these episodes hang limp on the clothesline.

With two directors and three credited screenwriters, this is a clear case of too many cooks spoiling the broth. The film takes significant liberties with the Newbery Medal-winning storybook, none of them helpful. The filmmakers add a clumsy framing device to open and close the action, clothe the tale's animal characters in an act of absurd prudery and invent a new, humanoid vegetable creature just to show off their visual effects capabilities. The film comes at you like an armload of pots and kettles clattering down the stairs.

The personal tone of voice that distinguished the book is reduced to overexplicit narration by Sigourney Weaver, underlining every authorial insight three times in red ink. And the point -- that people of all stations in life find true happiness in the love of their families -- carries a different emphasis when the story is told in visual terms. The moral of this fable seems to be that pretty girls deserve to live in castles and that coarse-featured, broad-beamed girls should be happy slopping pigs. Hans Christian Andersen's stories were authentically grim and terrifying, but it's not often you encounter children's entertainment so glum.

Colin Covert • 612-673-7186