When a strange little man dressed as a Conquistador comes clattering into the barn at the back of the Johnsonville farmhouse one night, Guster is forced to face the truth: he is now the most delicious thing in the whole world, and something terrible is coming to eat him. When Guster runs away from home in an attempt to elude the monster, he is kidnapped and taken to a city in a far corner of the Himalayas where he discovers a city made of pure ice cream. Now, with the monster returning soon, and the Mayor of the City determined to feed Guster to the beast at all costs, Guster must take courage in order to save the collapsing city and his family.