Coloratura gave up the city spotlights for a life in Ponyville with Applejack. For all its ups and downs, she wouldn't trade it for anything else. But "happily ever after" is still a long way off, especially when she still has her demons to fight.
Applejack finally decides that she needs to write a letter to one of her dearest friends, after the turmoil in her mind begins to get too much for her.