This story is a sequel to Mega Man: Operation Ponyville
It's been 30 years since the invasion. Those creatures...they never saw them coming. The Changelings swept in and took over, killing anypony that opposed. The Elements of Harmony aren't around to fight back, and the Royal Princesses aren't in any better condition. The ponies learned to live in fear, scared that their current day could be their last. The only hope they had is the rebellion group, the Maverick Hunters.
On a scouting mission, one pony discovers a robot sealed away from before the attack, one who provides the best chance of fighting back. He's the only robot in existence who can think for himself, and is in constant struggle with himself over what he's doing is right. He'll need to make friends with other Hunters to go against the Changeling Queen and save Equestria.
A psuedo-sequel to my first story. It shouldn't be necessary to read it, as the previous events are only referenced as history.