Nettchen thinks it is awful that the most attractive men are conscripted, as her Hans is among them. He is the piper of the 1st Guards grenadier regiment and not only gives the note for marches, but also charms girls’ hearts. Nettchen acts as postillon d’amour for the advocate Klette, the secret adorer of her mistress Charlotte Stelzenbach, who, however, has never answered the romantic letters that Klette writes under a pseudonym. The master and mistress have an argument once more because Charlotte does not believe Stelzenbach’s transparent pretexts for his long periods of absence. On her husband's departure, she goes to Klette, of all people, to file a petition for divorce. Shortly afterwards, Charlotte returns empty-handed since the advocate was not at home, having left a message that she urgently wishes to speak to him. In the meantime, Nettchen has received Hans and, on the unexpected return of Charlotte, hidden him in a chamber, suspecting that Charlotte's message has caused a misunderstanding with Klette. Indeed, a short time later the advocate appears, believing that he is at last accepted, and has brought along a whole dinner for an evening with Charlotte. When Stelzenbach, her husband, unexpectedly returns from his unsuccessful appointment, the situation becomes rather delicate. From his hiding-place, Hans watches the dramatic plot gradually tightening, and just at the right moment, he comes up with his "diabolic" solution.