Discord has lied to the Princess. Now he's keeping her captive.
Discord promised he'd use his powers for good, but one day, he decided he couldn't take anymore. As a child, he fell in love with Princess Celestia. But, she fell for his older brother, Craze. He seeks revenge on Princess Celestia, for he holds too much hurt.
He split Ponyville in three, the Unicorns, Pegasi, and Earth Ponies. He made the seasons longer, and on a special holiday, called, Lugyer, he would pull the luck of a draw, and murder a pony-In front of all of this "Ponyville" to see.
This time, the Mane6 cannot stop him. Applejack and Twilight have already been slaughtered, so without the Elements of Honesty and Magic, its up to ponies else…