On the celebration of his Hatching Day, Spike is depressed because he doesn't know where he came from. Princess Celestia gives him a map to the cave in which his egg had been found and he and his friends travel there. While they are gone the Princesses are attacked by the Changelings under command of their master. The mane 6 must then embark on a mission to save the Princess and stop the darkness before it can overtake all of Equestria but before they can do so they must come to know what it was that happened 1000 years ago that led to the birth of the Alicorns and the banishment of Tirak and his armies.