Muncle Trogg, the tiny giant, is worried. His home on Mount Grumble is about to erupt, and all the bigger giants can think about is celebrating the departure of the Smallings from down the mountain! Luckily for Muncle, his friend Emily hasn't abandoned him - and she has an idea. The giants might not listen to Muncle but they will listen to the wisest, most wondrous animal of all - a flying donkey!