Stone Soup is an old folk story

Folklore

Folklore consists of legends, music, oral history, proverbs, jokes, popular beliefs, fairy tales and customs that are the traditions of a culture, subculture, or group. It is also the set of practices through which those expressive genres are shared. The study of folklore is sometimes called...

 in which hungry strangers persuade local people of a town to give them food. It is usually told as a lesson in cooperation, especially amid scarcity. In varying traditions, the stone has been replaced with other common inedible objects, and therefore the fable is also known as button soup, wood soup, nail soup, and axe soup. In the Aarne-Thompson folktale classification system it is type 1548.
Some travellers come to a village, carrying nothing more than an empty cooking pot.