Nightmare Moon banished Celestia, only to be defeated by Ahuizotl. Ponykind were made the scapegoats to blame for her scourge. 1000 years they pray for a saviour to deliver them. Anypony will do. Enter the last hope, a pizza delivery dude.
The Cutie Mark Crusaders find, repair, and pilot a giant mecha from Earth's distant future, while dealing with every giant robot anime cliche in the book. This Cutie Mark Quest is a real Crusade.