The marriage of the celebrated operetta diva Vilma and the chamber singer Peter has come to an end. Peter, however, is intent on winning back his now ex-wife. So he’s come up with the idea of a guest performance in Venice, where the two will both appear. Vilma, however, has already found a new man – Niki. He’s a salesman and she wants to marry him. With the help of Annemarie, a friend, who has won a trip to Venice, Peter succeeds in diverting Niki, for he falls in love with Annemarie. Now the way is free for Peter to win back the ex-wife, who couldn’t care if he lived in a hole six feet underground.
The actor Ralph Gregor plays "Casanova" on the stage and everyone expects, that he also lives out the role in real life. Johanna Brinkmann, known as "Joe", tries everything to make her husband jealous of Ralph. Ralph, however, is actually dating his colleague Steffie. After a fight with her, he takes off on a short trip into the countryside and there gets to know the attractive Gertrude, with whom he falls in love. In short order, he proposes to and marries her. Soon, however, Gertude gets to know Steffie and Joe, who appear to know Ralph much better than they do, and Gertrude loses it.
After the death of his uncle, the owner of the Rhine based Bockelmann Sparkling Wine, Peter turns up for the reading of the will. Justus Bockelmann, a producer of mineral water, is confident he will inherit the business, but ‘for reasons of moral rectitude’ he has no intention of running an ‘alcoholic business’. The opening of the will comes as a surprise to all the potential heirs.