Having helped Diamond Tiara learn both the true meaning of her cutie mark and the value of friendship, the Cutie Mark Crusaders had just resolved that being together and helping others was what really mattered before they were engulfed by a bright light.
Finding themselves in a strange void, both their lives and those of all Equestrians are about to change. Hopefully Celestia and the former Elements of Harmony can figure out how make sure this change is for the better, because there's a new alicorn on the block, and they have a bit of a reputation for causing havoc.