The Little family adopts an adorably spunky mouse named Stuart (Michael J. Fox). Mr. and Mrs. Little (Hugh Laurie and Geena Davis) fall in love with Stuart right away, but their older son, George (Jonathan Lipnicki), isn't so sure. As Stuart tries to win over his new brother with hilarious feats of courage and daring, the family's cat, Snowbell (Nathan Lane), gets involved with a gang of shady felines who devise a dastardly plan to get Stuart out of the house permanently.