Teenagers Peggy Prescott and her brother Roy share a love of aviation that they inherited from their late father. Mr. Prescott had always dreamed of building an aeroplane that would be free of the defects of planes already invented. Peggy and Roy manage to build a plane starting with the framework their father had begun. Peggy christens it 'The Golden Buttefly' and she and Roy are determined to enter it in a young aviator's contest for a prize of $5000. The Prescotts need the money desperately to save the home they share with their aunt which is about to be taken from them by the rather nasty banker, Mr. Harding. Peggy and Roy along with their best friends, Jess and Jimsy Bancroft - also sister and brother, experience many adventures - many of them while flying the Golden Butterfly. A kidnapping, missing jewels and contact with some desperate characters are just some of what the Prescotts encounter in their Long Island village of Sandy Bay. There's never a dull moment for these two as they pursue their dream of flying. (Summary by Lee Ann Howlett.)