Months after the Battle of the Bands in the other world, Twilight and her friends are knocked out cold for a day, getting visions of a set of elements called the Pieces of Harmony. The Mane Six are sent on a quest to find the Pieces of Harmony, which have been banished to the other world. How to find them? Nopony knows. But perhaps Twilight's associates at Canterlot High can help them. But with worlds colliding and a new threat facing the heroines, they'll need help from some unexpected company.

Takes place before Legends of Everfree.
This story was previously "The Bearers of Harmony" before being rewritten, which is why the upvote and downvote count are at where they are.