Rick Heller is a juvenile delinquent who continues to get himself into trouble. To keep him out of mischief, his mother, Margaret, puts him to work cleaning the cage of a female western lowland gorilla named Katie. Margaret is teaching Katie to communicate through the use of sign language. When the owner of the gorilla, Gus Charnley, takes her away to become a flea market Sideshow, Rick decides to rescue Katie and take her on an adventurous journey to get her out of the country.