Some might be taken aback by an animated children’s movie in which the big finale involves a pretty princess who’s all trussed up as a meal for an army of ravenous rats. But though that’s where “The Tale of Despereaux” winds up—in a sequence that, along with a few others, will probably be too scary for very young kids—the picture’s real problems lie elsewhere. Though it’s nice to encounter an animated kidflick that isn’t crass or bombastic, this one is too complicated and sedate to stay in the memory.

Based on the Newbery Award-winning children’s book by Kate DiCamillo, the screenplay by Gary Ross is set in the kingdom of Dor, famous for its royal soups, and centers on a sweet little mouse, voiced by Matthew Broderick, who horrifies his family and the wider mouse community by refusing to scare easily and wanting to read books, especially those containing tales of derring-do, rather than eat them. The last straw comes when he actually talks to a human being—the kingdom’s sad Princess Pea (Emma Watson).

Pea’s morose because in the course of the kingdom’s annual Soup Festival, another rodent, the recently-arrived rat Roscuro (Dustin Hoffman), accidentally fell into the queen’s bowl and so shocked her that she dropped dead. In his depression, the king not only outlawed soup but rats too, forcing all of them to live in deep, dark underground caverns far beneath the city where they engage in arena rituals redolent of Mad Max’s exercises in Thunderdome.

It’s to that gloomy place that Despereaux, his head filled with tales of bravery and chivalry, is exiled by the mice for his unorthodox behavior. Meanwhile Roscuro, who’s rebuffed by the princess when he tries to apologize, joins forces with unattractive servant girl Miggery Sow (Tracey Ullman), to steal the crown for her, though he later repents when Pea is endangered by his fellow rats and aids Despereaux in her rescue. Meanwhile Miggery finds happiness when she’s reunited with her real father, a royal jailer, and the king’s cook, prodded by Despereaux, gets back to work with the help of his inspiration, a figure that composes itself into vaguely humanoid form from an assortment of fruits and vegetables, and invents a splendid new soup.

If this surfeit of plot and subplot sounds ungainly, it is; this isn’t really a tale but a collection of tales, and they don’t always dovetail very smoothly (bits and pieces of Miggery’s story, for instance, are simply inserted as needed). That explains why the presence of a narrator is required—a disembodied Sigourney Weaver, who supplies not only necessary backstory but even explanations of characters’ motivation as well as flat-out declarations of the morals one should take away with you—entirely non-controversial ones like “small doesn’t mean weak,” “be true to yourself” and “family will out.” The fragmented nature of the piece, along with those oddly dark passages, make “Despereaux” less family-friendly than many of the other animated movies out there.

But there are compensations. One is the quieter, less rambunctious approach than is usually found in animated fare. This picture moves relatively slowly, as unafraid as its mousy hero to opt for deliberation and gentleness rather than noise and bustle. Another is the look of the widescreen images, which eschew the garishness so commonplace nowadays in favor of a smoother, more atmospheric appearance emphasizing muted colors. And while Broderick gives a rather bland voice to Despereaux, Hoffman plays Roscuro with the range he might bestow on a live-action figure, giving the rat a psychological complexity any human character might envy, and Ullman brings similar fullness to Miggery. The remainder of the voice cast is studded with big names, but they make less of an impression than you might imagine; apart from Christopher Lloyd, whose growl is unmistakable, they sound rather anonymous. Even Watson’s Princess Pea is pretty pallid.

“The Tale of Despereaux” is admirable for its attempt to replicate the book’s restrained, temperate tone, and visually it’s pleasant in an old-fashioned way. But its fragmented narrative, preference for somber understatement and occasional frights make it a nice-looking, respectable but oddly unsatisfying family fable.