Starlight's Courage, the second of the series, introduced a villian. I mean a real "bad guy" not just the Magnificent Four, Miranda's nemeses in the form of the four girls in her class who treat her and her friends with malice.
The "bad guy" is Martin Hicks who drifts through the little town, looking for work before moving on. Mr. Taylor, desperate for help because of Higgins's disabling injury, hires him to take care of the stabled horses. An instant dislike springs up between the man and Starlight, and the man and Miranda. He doesn't last long at Shady Hills, but he is a vindictive man and an escapee from an institution for the criminally insane. And he has it in for Miranda and Starlight. (You'll have to read Starlight's Courage to see what happened.)
When I revised Starlight's Courage a few years ago, I left a small possibility for his return in another episode. Will there be a number seven to the saga of the horse and his girl? If there is, will Martin Hicks be in it? Ah, that's the question I have yet to answer. I'm waiting for Miranda and Starlight to give me a clue, for my characters, though fictional, lead the story and tell me what they would do, while I just write it down.