Everypony has known Derpy Hooves to be a Ponyville staple for as far back as they can remember. Their mail has always gotten delivered on time, at least as long as everypony can remember. But when Twilight Sparkle is doing some research for her upcoming book on the history of Ponyville, she comes to startling realization: nopony can actually recount when Derpy came to Ponyville, or why she came there to begin with.
And when Twilight goes to ask her, she finds she may not have been prepared after all, for the repercussions of her one simple question: Just who is Derpy Hooves... and how far is she prepared to go for the ones she loves?
Written for the May prompt, "the first time", for the now-revitalized Competition Arena. Rated just to be safe.