Doktor Krall fights furiously against diseases and depressions that can affect rats, paddles, rabbits and horses. But also against the enormous ambition and energy of his assistant Rolf.

Doktor Krall often comforts himself by playing his beautiful Hammond organ in walnut tree. It is so soothing. Among other things, Rolf is infected with insomnia from a tsetse fly and he destroys a lot of the clinic and lab by accident, while trying to produce a miracle cough medicine. The desert rats Hans and Gretchen plays a minor role in this too.—Ulf Kjell Gür