"The Storyteller," by Saki (whose real name was H.H. Munro) is about a woman who is travelling by train with two young nieces and a nephew. The Aunt tries to entertain the children by telling them a story about
a little girl who was good, and made friends with every one on account of her goodness, and was finally saved from a mad bull by a number of rescuers who admired her moral character.
The children find the story boring because of its very traditional moral stance that good things happen to good people.
A bachelor is sitting on the same train observing observing the Aunt and her young charges. He offers to tell them a story.
The bachelor's story is about a girl who is "horribly good," so good that she wore on her dress three medals for goodness. As a further reward for her goodness, the girl is invited to visit the park that belongs to the local Prince.
As the girl strolls through the park, she is attacked by a wolf. The girl hides behinds behind a bush, but the wolf eventually locates her when her medals click against one another. The wolf devours the little girl.
The nieces and nephews love the story.
What is the theme of this story?
The author seems to be poking fun at the kind of dull, moralistic tales that were often told to children. In this story (as in real life) the children prefer the story of a goody-goody who is destroyed by her own goodness.
On another level, the author may be questioning the religious notion that good things happen to good people. Saki was hardly the first person to realize that righteous people often suffer the same (or worse) fate as evil ones. The author of the Biblical book of Ecclesiates, for example, comments (7:15):
In this meaningless life of mine I have seen both of these:
the righteous perishing in their righteousness,
and the wicked living long in their wickedness.
That you can't always be too perfect.
If you need any more clarification. I read the story and the answer above is correct