When Emma Dollybutt, her brother Ivan and his best friend Conrad are taken to the zoo, they are not expecting Great Uncle Lancelot to arrive in a balloon. Here, they learn about Great Uncle Perceval's fantastic discovery: a dust that enables people to talk to and understand animals.

Lucretia More, the head of the world's largest pet food company, also knows about Perceval's discovery and wants that dust. Perceval, Lancelot and the children have to make sure she does not get it. They plan to keep it hidden from Lucretia while Uncle Perceval finds a safe place to continue his research.

Lancelot and the children embark to a breathtaking journey around the world in his fabulous flying machine. The greedy Lucretia constantly chases them and her simple-minded assistant but the children and Lancelot can call on the animal world to help and protect them.