The Long Night.
It means different things to different ponies. In Canterlot, Celestia traditionally throws a huge party. Meanwhile, all the pegasi retreat to their sky cites, and all the other ponies from Manehatten to Ponyville hurry home before dark, and lock their windows and doors.
Every year before now, Apple Bloom has always been sent away to stay with her friends or family during the Long Night. But this year, despite Applejack's objections, Granny has decided she is old enough to stay on the farm.
Apple Bloom is excited to finally be allowed to spend the Long Night with her family. To see just what all the fuss is about. Just what really goes on that she was too young to be a part of before now?
This year she gets to find out. But before the Long Night ends, she will wish with all her heart, that she hadn't.