In 1756, a masked ball was officially celebrated in the Dresden Palais of the Saxon Minister Heinrich von Brühl. Unofficially, however, talks are taking place with the envoys of Austria, Russia and France with the aim of conspiring against the Prussian King Frederick II. The Prussian envoy, Major von Lindeneck, succeeded in bringing a copy of the concluded secret treaty to the Prussian king. Friedrich consults with his generals, who urge caution. Friedrich is stunned by the reaction and now develops a counter-plan. To do this, he sends von Lindeneck back to Dresden. However, the latter is not very enthusiastic about this, as he thinks he has reason to doubt his wife Blanche's marital fidelity, and he now has to leave her alone.