With the operetta Die Fledermaus, the King of the Waltz created a masterpiece of its genre that has never been surpassed: brilliant music combined with a stinging comic plot that has not a hint of cheap sentiment.
The plot revolves around a ball given by Prince Orlofsky to which all the characters are magnetically drawn. The only exception is Alfred, the tenor who is in love with Rosalinde, and who shoots to the fringe of events like a comet: The maid Adele believes she has been invited to the ball by her sister Ida and is forced to invent a touching tale of a sick aunt in a ruse to ensure that she is finally given the evening off, her employer, Gabriel von Eisenstein, a man of private means, who is persuaded by his friend Dr. Falke to amuse himself at Prince Orlofsky’s instead of reporting to prison to start a sentence he has received for insulting an official. Of course, Dr. Falke has ulterior motives, as he wishes to take revenge on Eisenstein for once having made a fool of him in front of the entire city. On that occasion, the two men had attended a masked ball and Falke, who was dressed as a bat, had got drunk. Instead of taking him home, Eisenstein had abandoned him to fall asleep in the city leaving him to make his way home the next morning in his costume. Falke now sees his opportunity to avenge himself and for that reason also invites Eisenstein’s wife, Rosalinde, to the ball. Prior to this, she had been extremely confused when after Eisenstein's supposed departure to goal, her former admirer Alfred turned up and began to importune her; he was then arrested by the prison director Frank who mistook him for Eisenstein. After having performed his legal duty, Frank goes off to the ball at Orlofsky's. In Act 2 all the complications arranged by Dr. Falke come to magnificent fruition. To his amazement, Eisenstein meets his maid Adele there, who impertinently denies her identity, makes friends with the prison director and finally falls in love with his own wife who is disguised as a Hungarian countess. In Act 3 all is finally revealed. This Act takes place in prison and is given a dubious note in the form of the gaoler, Frosch, who is never sober. One by one, all the characters arrive: first of all, the extremely hung-over director Frank followed by Adele, who is seeking a patron willing to finance her training as an actress, her sister Ida, then Eisenstein, who is astonished to find that he has already spent the entire night in prison. When Rosalinde also appears and demands to speak to a notary together with the imprisoned Alfred, Eisenstein disguises himself to take the place of the notary Dr. Blind and thus discovers the truth about the previous evening’s events. Fortunately, he can be persuaded that it was all part of Dr. Falke's revenge and so all’s well that ends well, all the more so as Prince Orlofsky does indeed decide to sponsor Adele's acting career.