After Queen Chrysalis's defeat, she has been seeking revenge. Meanwhile Discord breaks out of stone and decides to team up with the Queen. Together, nopony can stop them from thier rain of chaos and disharmony. Twilight and her friends discover that their powers combined has a stronger power than the Elements of Harmony.

Since Princess Celestia is tied up with indestructible rope and Luna sleeps during the day, Princess Cadence is the only one they can get to for help. But Princess Cadence has a magical portal to another dimension. She loans it to Twilight to get help from stronger creatures that are not from here. What they find is more than they had expected.