In this play, Pocci takes up a literary genre that was very much in fashion at the time, that of the Robinsonade, but mischievously transposes the adventures of Casperl-Robinson to the shores of Lake Starnberg, some twenty kilometres from Munich, 'in dem cultivirten Bayern' ('in the civilised country of Bavaria'). Pocci is at home here, as he lived on the shores of the lake in Ammerland. The first part of the play, which takes place in Munich, alludes to his work as a satirical cartoonist: Pocci had made a name for himself in the Munich periodical Die fliegenden Blätter for the caricatures of German civil servants that he delivered with the character Staatshämmorrhoidarius. In Casperl als Robinsohn, Mrs. Federspitzen reports that her husband always gets angry when this name is mentioned in front of him: 'daß sich auch kein Paragraph im Strafgesetzbuche vorgefunden, den schändlichen Erfinder dieser Figur lebenslänglich einzusperren [. ...] ist wirklich ein Mangel in der Gesetzgebung!" "That there is no article in the penal code to lock up for life the unworthy inventor of this character [...] is really a defect of our legislation!"

Mr. Casperl, a wealthy man of private income, has an appointment with Lieutenant Säbelmaier and the wife of the secretary Federspitzen for an excursion to Lake Starnberg near Munich, but his barber comes too late and he has to leave in a hurry to catch his train, which had been announced late. In the second part of the play, the boat of the three excursionists is wrecked by a sudden storm on the lake. Säbelmaier and Mrs. Federspitzen probably managed to save themselves. Casperl has been living like Robinson for eight days in a deserted forest by the lake. He finally meets a sheep with whom he can talk about philosophy, because it is in fact the reincarnation of a professor and living proof of the truth of metempsychosis. But they argue and the sheep flees in the face of another coming storm. A hunter then finds Casperl passed out and wants to bring him to justice as a poacher, but ends up recognising him as the man who disappeared eight days ago, and Casperl concludes by recommending that the audience take the steamboat instead.