(Note: It is highly recommended that you read My Little Pony, Friendship is Magic: Stallion Edition chapters 1-12 first. Otherwise, things will not make sense.)
Everyone knows that a cutie mark is what defines a pony, and that it is among the most important moments in a young pony's life.
But every cutie mark has a story, that tells something about the pony that it is a part of. Some stories are more interesting than others, but no two stories are ever the same.
When a trio of fillies (and one colt) set out to learn from one stallion how he got his cutie mark, they will discover a mystery like no other. And the truth, will redefine a particular friendship in a very important way.