A long long time ago evil king Vivace wanted to conquer the world and called out an dangerous force, that he was unable to control. After a years of fight - the force was defeated and king Vivace gone with it. Everyone was sure, that this force will never return, but after thousands of years it has returned and want to destroy all the known world. Who could fight with it and return the harmony to the entire world? Only legendary Keepers Crystal can save the world from destruction, but all the known components were lost in time and only one fragment were saved - The Equestrian Crystal - the heart of the Equestria, that keeps balance in all the kingdom.
And all turn out, that the fate of the world is in hooves of only one pony and his friends.