The topic of the play comes from a children’s book that has been very popular in Germany since it was first published in 1844. Written by psychiatrist Heinrich Hoffmann, the book is a collection of fables in verse, illustrated by the author himself, which stage several cases of misbehaving children, and the punishments they receive, which are sometimes cruel. Heinrich Apel borrows from Hoffmann his eponymous character, Struwwelpeter (Shock-headed Peter, also translated “Slovenly Peter”), a boy who never does his hair and does not trim his nails. The puppeteer, however, invents a new story for him, only keeping some elements from his predecessor. Thus the punishment inflicted upon Peter comes from another fable, The Story of the Inky Boys: three children are dipped in ink by the Great Saint-Nicholas, as a punishment for having mocked a black person. It has not gone over Heinrich Apel’s head that one of the rascals is named der Kaspar, like the favourite character of German puppet theatre… who of course appears in the play.

The widow Schulzen is as happy about her daughter Rosa as she is worried about her son Peter. This wild child with tousled hair and long nails stopped going to school, has no respect for anything or anyone, and his persistent acts of mischief targeting the villagers could send him to prison. Rosa leaves the house and sets out to find the wizard Albaras, who appeared to her in a dream and promised to improve her brother’s behaviour. Her quest takes her to the court of King Arthur, whose son Tugendreich is old enough to marry and take charge of the kingdom, but wallows in the increasingly insolent jesting of his servant Kasper. His jokes go far enough that he is soon driven out of the kingdom as a bad subject. He wanders in the mountains where Albaras’s castle stands and, reformed, decides to become his servant. In the meantime, Peter became a drifter: he too crosses paths with Albaras’ servant, but he makes fun of his face because it is black, and spirits start possessing him. Rosa comes in, after a long journey from the king’s court. Albaras urges Peter to turn his life around, but he refuses stubbornly. As a punishment, the spirits dip Peter into a large inkwell, until he is completely black. As for Rosa, she came back to her mother’s house. Kasperl joins them with Peter, who is now clean and obedient. Prince Tugendreich then comes in and proposes to Rosa, who he saw at his father’s court. Albaras appears and ends the play.