Devilius and Monti the Rat scheme about a devious new plan. Together, they lure Pumperl, Amadeus' sweet little dog, into the hands of a dogcatcher. They hope he'll be too busy searching for Pumperl to perform at the silver wedding anniversary of his friend Kati's parents. This would enable Devilius' nephew Mario, who fell madly in love with Kati, to take Amadeus' place (and his music). Unfortunately for them, the bad guys didn't count on Pumperl's cleverness.