Here's why:
* "Mares and Foals" could be a title of many things: A book, a painting, a song, a movie, a photograph, etc. Each of these would have a different way of telling a story.
* Stories can be told in many ways: A story doesn't have to be a linear narrative. It could be a collection of images, a poem, a piece of music, or a documentary.
To answer your question properly, I need more information! Please tell me:
* What is "Mares and Foals"? Is it a book, a painting, a song, etc.?
* What is the context? Where did you see or hear this phrase?
Once I know more, I can help you figure out if "Mares and Foals" tells a story.