Golden Gate has a dream that was described to him by his sister two years ago. His sister is now dead. Because of this dream, he is now next. The Shadovens have Marked him.
The Shadovens, evil, shapeshifting creatures, are after him. And they want to make his fate the same as Liberty Bell's.
With the help of the Cutie Mark Crusaders, he must defeat the Shadoven queen Enigma and free the other ponies that are Marked.