Many years have passed since the Coronation of Princess Pinkie Pie, the Princess of Laughter and last Princess of Harmony to be Crowned. All of the Princesses of Harmony(Except Twilight Sparkle, who was deemed too important by Queen Celestia, and Fluttershy, who chickened out) went off on a mission to destroy the Dark Lord, Eresar and never returned. The Cutie Mark Crusaders have gained their Marks and grew apart. Now Sweetie Belle's Half-Crystal Daughters must unite with the children of the other Crusaders to defeat the Dark Lord once and for all.