This episode page has been compiled from the episode description at the NDR website.
Nils, Samson and Finchen plays Ludo, when the get enough of the noise coming from Rumpel and they go over to him to see whats going on. Rumpel are listening to what he thinks are music, more specifically the 3rd noise symphony by Ludwig van Krachhoven. Nils asks Rumpel not to listen to that noise all day, Rumpel gets an idea he are gonna compose his own symphony.
Rumpel have set up various instruments for his symphony. Cans on a string, a pair of typewriters and some horns, however he soon discover that he can't play the instruments at the same time.
Rumpel decides to try and put the instruments closer together and he gives it another try but are still finding it difficult to reach the various instruments in time. Meanwhile Nils, Samson and Finchen conclude, by the sounds they hear from Rumpel, that he might need some help. They go over to him and volunteer to help play his symphony. Rumpel are reluctant at first after all they are not Grouches, but ends up accepting their help, with the requirement that he are gonna be the conductor.
Before they start Nils insists that they test their instruments first and afterwards they start to play as Rumpel does the conducting and singing. Rumpel are happy with the result.
They continue to play, but it's starting to get out of hand for Rumpel as his musicians are starting to find it funny. Rumpel are shocked a Grouch symphony are not supposed to be fun, but loud and horrible. Nils, Samson and Finchen confirms that it's loud and horrible but still fun. After thinking about it Rumpel accepts the fact that the symphony are also fun for some.