Twilight loves to learn. When she asks to study abroad, Luna is quite happy to send her to a place full of new information and a rich history that is irreversibly entwined with Equestria's: the moon.
Twilight now has has a veritable smorgasbord of information in front of her: The story of Nightmare Moons' imprisonment, the truth behind various questions about the moon, the odd natives...
Oh, yes, there's life on the moon. Highly eccentric life that Twilight is going to have to live alongside, cooperate with, befriend, and otherwise not be driven mad by. How long will Twilight be able to stay, and how many dark secrets can she find in that time?