There is a mouse in the workshop, and Meister Eder would rather get rid of it, but Pumuckl insists he wants to keep it as a pet. That is, until he realizes that work is involved in having a pet.
Meister Eder and his nephew go climbing a mountain, and when the weather changes suddenly, and the younger man irresponsibly wants to head further up the mountain, Pumuckl saves the day.
Pumuckl finds out that his good intentions to make happy two boys playing treasure hunt, lead to complications when he wants to retrieve the "treasure" he has planted for the boys to find, and return it to its rightful owner.
Pumuckl gets wet while he's visible and catches a cold. When Meister Eder calls the doctor for advice, his story is taken for the ramblings of a man with a fever and the doctor comes and treats him instead of telling him how to cure the little imp's cold.
Meister Eder is under pressure because he has a deadline for finishing an important order. And with the master stressed out, Pumuckl gets blamed for everything that goes wrong, even though, just for once, none of it is of his doing.