Just part of what will become a an on going series of stories. Book One covered Starlight Glimmer. the next few will cover Applejack, Rarity, Twilight, Rainbow Dash, and maybe Trixie and Derpy.
Applejack would learn that her family history wasnt always so bright and happy like she had been told when she was a young filly.

Her ancestor had been involved in one of the most bloody battle in the history of Equestria. And it all started with a raid on her ancestors farmstead and lead to one of the longest wars ever recorded.

And she discovers that one of her friends in the present is responsible for nearly unleashing an ancient evil upon the lands of Equestria. Something that will haunt the two of them forever.