This day was suppose to be perfect
The kind of day of which I dreamed since I was small
But now we've made a mistake
There's no wedding, dancing, or cake,
This day should have never happened at all...

It was suppose to be the best day for everyone, where Princess Cadenza Mi Amore and Captain Shining Armor were suppose to get married. Unfortunately, things ended so badly, where the bride turned out to be a wicked Changeling Queen who nearly took over Equestria, but the love of the two banished the Queen and her Hive far far away.
However, it came with a terrible price. Twilight Sparkle, the faithful student of Princess Celestia, was the first to know something was wrong. But no pony listened to her, and after a failed desparate attempt, Twilight was cast out of the wedding by her brother, and her friends and mentor abandoned her in her time of need, planting the seeds of darkness in her heart.
Now, though the threat has come to an end, Twilight Sparkle lashes out at her friends and brother, and turns them away in pain and anger. Unable to forgive her friends, and herself, Discord, who is on the verge of breaking free from his prison, convinces the unicorn to abandon friendship, leading her down a road to a dark path, to awaken an evil that was sealed away long ago, and to make matters worse, a Crystal Kingdom has emerged in the North, along with an wicked unicorn who wants to burn it all to the ground.
Meanwhile, it has been months since Master Xehanort's end. Things have gotten back to normal, except for Sora. He has been out of place lately, which many believe is Post Traumatic Stress from the Climatic Battle. He says that he's fine... but maybe he's not. But the magic in the universe is fading away, which brings him, Donald, and Goofy back into action. They are tasked by Yen Sid to head south of Equestria and find Twilight Sparkle and restore the connection of the Elements of Harmony, while Riku and King Mickey go north to investigate the Crystal Empire.
But a great shadowy evil has awakened, with Maleficent and Pete taking this opportunity to take over Equestria, with help from a strange individual who is looking for something in the Land of Ponies.
Can our heroes save Equestria and stop the darkness? Can Sora find Twilight and restore the magic of friendship, but can he also conquer his inner demons and come to terms with his own struggles?
Join them on this epic adventure filled with musical songs from My Little Pony and other famous musical classics and movies. It will have magic, drama, comedy, action, chaos... and of course, Friendship!

Despite the MLP characters and disney characters included, the story is rated T for the Fantasy Violence, Comic Relief, and Animated Blood, with Mild Language included.
Keep in mind that this is also an AU, so the story both follows and doesn't follow the ending of Kingdom Hearts III. You'll see when more of the story is posted.

Anyway, hope you guys enjoy the story!
May your hearts be your guiding key!
Also, keep an eye out for Secret Reports in the notes... They contain some very interesting information!