Early on in the story, the bachelor points out that the aunt does not "seem to be a success as a story-teller." She has attempted to quiet her two nieces and one nephew with a story that was completely unsatisfactory to the children, and they were disinterested and not entertained by it at all. In fact, it prompts even more rude comments and questions from the children, because it is so boring and predictable.
In a desire to keep the children quiet for just a few minutes, the bachelor begins to tell his own story. In it, a girl who had been "horribly good" was awarded with a private entrance into a special garden. The garden was full of pigs, and these attracted the notice of a wolf. Because the child was so clean, the wolf spotted her gleaming white frock right away, and when she hid in the bushes, her medals for goodness clinked together, giving away her location; thus, the wolf ate her. In the end, the bachelor succeeds where the aunt failed, and she insists that he has undone years of careful teaching with his story, calling it "improper." He then calls her an "unhappy woman," because, now that she's called the entertaining story "improper," the children are going to keep asking her for improper stories in public! This is certainly going to make her unhappy.