This is just a hypothetical guesstimate as to the main story of Legends Z-A. I will not call this a leak, as I have no way to know of how close this might be to the actual truth. The more I think about it, the more that some of the leaks begin to start making sense.

At the end of X & Y, we meet the character Emma and her partner, an espurr named Mimi.
The detective named Looker gives Emma the detective agency before he leaves for his next journey elsewhere.

*These next parts from here on are possible to the story of Legends Z-A*

While on a case one day, Mimi sacrifices itself to save Emma. This would be in similar contrast to how Looker also lost his previous partner.
Fast forward a bit, now due to the high-tech redevelopment of the city, new technology is being introduced by the quasartico company to bring the city to an updated modern era.
Emma, having been looking for a way to bring Mimi back to life, discovers the history of the region and how the old king built a machine to revive his floette over 3000 years ago.
The main conflict of the story would revolve around how Emma is seeking to use the new technology from the redevelopment of the city to build a new machine to revive Mimi.
In order to complete the new machine, a 'catalyst' would be needed. Something that is already infused with enough eternal power to already have immortality... Floette.
Zygarde travels to the city because it senses the ecological imbalance caused by the new machine and the gathering of the life/death energies.
A battle between Zygarde and a rampaging Floette, possibly possessed by the energies, would ensue.
A sacrifice would be made to stop Floette and to stop the machine.

Like I said, this is only a guess.
There is something else that matches up.
'Z-A' could be a reference to something called "Eternal Return", or in technical sense "history repeats itself", in this case, a repeat of the ultimate weapon. And we know that 'Legends' is used for old history of a region.

>>57986529 (OP)
All you did was look at the already existing leaks
We already know the final fight involves Zygarde and you battling against Mega Floette fused with the tower with a lot of Floettes appearing around the city

>>57986627
We don't know that at all hell the emma leak isn't even crediable because everybody always assumed if she ever showed up again she'd be wearing a Looker like coat to acknowledge his influence on her since she can't acknowledge the MC because as far as the games have been concerned the MCs don't really exist in the world.

>>57986696
>she can't acknowledge the MC because as far as the games have been concerned the MCs don't really exist in the world.
I think Calem/Serena are going to appear in this one. I mean, there's the player and rival this time.

>>57986727
No they aren't, Herbert/Hilda didn't appear in Black and White 2 even through their friends did, their mom did, their house did and the characters mention them constantly, they excused their absence by saying they left the region to chase after N who also shows up yet N eventually leaves releasing his dragon to Nate/Rosa and still no Herbert/Hilda, that plotline had to wait until battle masters to finally have a resolution

so no, I don't expect Calem or Serena to appear in this game the most we will probably get is "that brave trainer and their companions" line from AZ at some point or from Emma if that's really her

>>57986529 (OP)
What if, that's not even Emma, and is someone that "transformed" their appearence using the Essentia suit? I don't know who or why would do it, but we know from X&Y that the Essentia suit can completely recreate the appearence of someone else. So maybe someone (from Quasartico, I suppose...) steals the suit and messes with it until it can totally recreate Emma's appearence. And since Emma is a renowned detective now, either nobody would suspect "her" (the one with the Essentia suit) always being around when shit goes down, or suspect the actual Emma, and they get away with it until we, the MC, find out. I mean, Emma seems quite suspicious in the box art.

>>57987145
That looks way too farfetched

>>57988057
Yeah, I know, it was mostly a "subvert your expectations" kind of what if...