in a nutshell:
- a top brass in the military tried to smash the moon onto eorzea
- he was defeated
- his subordinates did not reconcile with his defeat and proceeded with he conquest, believing the fall of the red moon would give them tactical advantage
- the battle in the movie took place. bahamut was unleashed
- prior to the battle, the old guy made the adventurers go around the continent to pray to the gods in a bid to summon them to resist the red moon
- the gods answered the prayers, but their efforts to contain bahamut was futile
- the old guy did some spell which saved the adventurers from bahamut\\'s wrath

*spoiler*














you are the adventurer the old guy saved. memories of you were erased from everyone\\'s head, but the memory returned at the end of the story.

what the old guy did to you is unclear, and why he did it was also unclear, and the reason for this memory erase is also left unclear.