It was after they got their cutie marks, that the Cutie Mark Crusaders get the chance to go to Canterlot with their families and celebrate Hearth's Warming Eve. A time full of fun moments, chatting with friends, and many more activities. For Luna however, it is a reminder of all of those positive plus one negative she will be the only one to remember.

The Cutie Mark Crusaders ever so curious, follow her through the whole castle avoiding a few obstacles along the way but what they discover will forever change their understanding of what Hearth's Warming truly means to the Night Princess.

EDIT: Link to a contest thread right here! Holiday Spirit Contest This isn't really important, but it's one of the rules for the contest at hand, so I had to obliged