The fourth adventure for young inventor Harley Hitch.
The Aviation Parade is coming to Forgetown this summer, and Harley has her sights set on creating a flying machine that will really stand out: a robot hippogriff! And if the creature impresses Cosmo's mum enough, surely Cosmo will be able to keep it as a pet?
But Harley wants the flying machine to be a surprise for everyone. She soon finds that keeping secrets leads to tricky explanations and lots of trouble - especially when REAL hippogriffs arrive and cause chaos!
A rollicking adventure that celebrates STEM learning!