Hannes's class performs a play in the city park. It is called the "The Robbery of the Tiger Duck". When the nasty mouse sheriff sees the announcement poster, he senses his chance. He will play in this piece! When the curtain rises, a rather unhappy Hannes stands on the stage. Ironically he must play the donkey of Prince Emmentaler and wear dog-ears. But then he is wide awake at one stroke. He discovers the mouse sheriff in the dragon's costume. The mouse grins his wry grin and claws the tiger duck. In order to save her, Hannes has to intervene in the plot and transform his role a bit. A wild hunt in the middle of the stage begins. Teacher Birkenpappel looks through the book in despair. What this donkey does is not in his book! But the audience is thrilled. When Hannes catches the Tiger Duck from the Mouse Sheriff in the grand finale, the jubilation knows no bounds.