A diminutive mouse strives to make a mammoth change in his troubled kingdom in this adaptation of author Kate DiCamillo's Newbery Medal-winning children's book. A long time ago, in the distant kingdom of Dor, a horrible accident broke the heart of the king, left a beautiful princess crestfallen, and filled the townspeople with despair. As the sun disappeared from the sky and the flowers were drained of color, the laughter slowly ceased in this once-magical land. It was into this darkened world that a tiny mouse named Despereaux Tilling was born, and while this virtuous little rodent may have been short in stature, his bravery was ultimately too big for such a small world to contain. An unlikely hero with oversized ears and a discernible wheeze, Despereaux was taken with tales of chivalry, and longed to one day become a noble figure among his people. Sometimes in order to realize their true destiny, heroes must first experience great hardship, however, and when Despereaux fails to adhere to the rigid rules of his society, he is banished from Dor.

Later, while exploring the outer realms, the lonely Despereaux is joined by a kindhearted rat named Roscuro. Roscuro, too, has been excommunicated from his homeland, and still cannot stand to look into a mirror lest he be reminded of his painful past. Later, as Despereaux embarks on a treacherous quest to rescue the endangered Princess Pea, Roscuro is set down the path of self-destruction after receiving a painful rejection from his highness. Now, on their way to realizing their extraordinary destinies, these two unlikely heroes will face off against the malevolent leader of the sewer rats, who is plotting revenge on humans from his subterranean kingdom; befriend a common serving girl who longs to become princess; and meet a whole host of colorful characters that they will never forget.

Matthew Broderick, Dustin Hoffman, Emma Watson, and Tracey Ullman lead a powerhouse cast in this animated feature produced by Gary Ross and Allison Thomas. Also lending voices to the project are Sigourney Weaver, Kevin Kline, Stanley Tucci, William H. Macy, and Christopher Lloyd.