Von Mäusen und Lügen: The ENT doctor dr. Arnold Fischer, called Arnie, always tries to please everyone. His friend and colleague Gregor is quite different: Purposeful and enterprising, he thinks especially of his own progress. Together, they want to expand the practice to a state-of-the-art tinnitus center. For this they need the neighboring apartment, but lives in the Mathilda, in which the shy Arnie is secretly in love. He does not have the heart to show Mathilda out of the apartment. And so Gregor tries with not always fine methods to get rid of the unpleasant tenant