When the Littles go to an orphanage to adopt a new family member, their son, George, insists on a little brother as opposed to a big one. His request is honored more literally than he ever imagined when a charming young mouse named Stuart is chosen. While George is disappointed and initially unwelcoming to his new brother, the family cat, Snowbell, is even less enthusiastic at the prospect of having a mouse as his "master" and plots to get rid of him. Against these difficulties, Stuart resolves to face them with as much pluck, love and courage as he can muster. In doing so, he shows his beloved new family that great things can truly come in small packages.

When the Littles meet Stuart at the orphanage, he is reading the book "Little Women".

Snowbell:
Didn't your mother warn you that you shouldn't go out into Central Park at night?


Smokey:
My mother was the reason you shouldn't go out into Central Park at night.

Errors made by characters (possibly deliberate errors by the filmmakers): When George comes into the room when they are playing the piano he says, "Is that G stuck again?" when actually the stuck note was a C.

Composed by Burt Bacharach
Lyrics by Tim Rice
Produced by Burt Bacharach & Elliot Lurie
Performed by Lyle Lovett
Courtesy of Curb/MCA Records