After Princess Cadence is kidnapped by changelings in the middle of the night and they threaten to kill her unless given "food". Celestia decides to get her elite team to rescue her. She sends the mane 6 along with the Wonderbolts as back up. From there they embark on a dangerious as hell mission, but they have plenty of back up to help them achieve this incredibly sketchy as hell Operation.
This is based mostly off the game ARMA 2 at least the idea was from it.
Also final note- if you want to suggest the loadout for each of the mane 6 (and also the Wonderbolts) go nuts. Just know that all the guns will have to be from ARMA 2 or ARMA 2 Operation Arrowhead.