Many of the charms of Kate DiCamillo’s best-selling children’s book are lost in this British animation by Dreamworks alumni Sam Fell (Flushed Away) and Rob Stevenhagen. Matthew Broderick gives voice to the title character, an adorable mouse with huge ears, and Emma Watson (of the Harry Potter movies) is the kidnapped princess he gallantly rescues, who looks like Mia Farrow. The imagery is colorful and artfully rendered, but the filmmakers, favoring technological wizardry over story, have beefed up the narrative with teeming rodent civilizations, a seafaring sequence, and gladiatorial action pieces. With the voices of Dustin Hoffman, Tracey Ullman, Kevin Kline, Ciaran Hinds, and Sigourney Weaver, who provides the arch and distracting narration. G, 95 min.