please explain the plot of final fantasy fourteen to me

There are four elemental crystals that maintain the balance of the world but they've been corrupted by the evil empire so you have to fly off the floating island you never realized you lived on so you can go to the moon and then the bad guy merges the two worlds back into one and then causes massive global destruction so you have to follow him into a crater to release the holy spell that will destroy the meteor he summoned in order to compress time and then you discover you were born on another world and you tell your dad you hate him and he has no idea who you are when you fight him but then it turns out it was his plan all along.

Also there are summon monsters.