What do you do when your best friend's a 400-pound gorilla? Anything she likes.

Rick Heller is a juvenile delinquent who keeps getting himself into trouble. To keep him out of trouble his mother puts him to work cleaning the cage of a gorilla named Katie which she is teaching to communicate through the use of sign language. When the owner of the gorilla takes her back to become a flea market freak Rick takes it upon himself to break Katie out and take her on an adventurous journey to get her out of the country.