I have a theory for what the plot of Pokémon Sun and Moon will be. This is the 20th Anniversary generation of games, so they will definitely try to be as epic as possible. Firstly, I imagine that the Pokémon Roster will go all the way to 999, and the Legendary revealed for the third game will be the 1,000th Pokémon.

So the games might start out similar to Ruby and Sapphire. Two teams Team Sun and Team Moon will have an idea to make the world brighter or make the world darker, respectively. Team Sun would still be wrong because they are trying to force the world to be a better place.
Later on, they will eventually awaken their respectively Legendary Pokémon. I don't know how the first two games will finish.

But I do have a theory for the end of the third, which might be Pokémon World or Pokémon Earth. What if there was a huge Pokémon War? While Team Sun and Team Moon are messing with the forces of light and darkness, it is affecting the Pokémon. It is corrupting some of them. So you will be able to catch Dark versions of all of the Pokémon. Maybe. Soon, more and more humans will start disagreeing over whether the world should be brighter or darker. Team Sun and Moon then awaken the two Legendary Pokémon that the game centers around. The Pokémon turn out to be enemies and starting fighting each other. This causes weird things to happen on the planet. Then the humans and the light Pokémon will battle the corrupt humans and the dark Pokémon.

So while all this is going on, you will be battling Team Sun and Moon. You defeat them and they come back to their senses. Then some Pokémon Master will come out and say of a ancient prophecy or something that told of a Pokémon on the planet that would bring peace again when this war happened. So you go on a quest to awaken this Pokémon. The 1,000th Pokémon. Pokémon World. You succeed. Then there might be a way that the Pokémon World will calm down the Pokémon and people. But as that happens, a greater threat arises. Maybe a dark version of Pokémon World. Then it will show all of the Pokémon using all of their strength to work together and defeat this evil Pokémon. But the only one who can defeat him is the greatest friend and trainer of Pokémon: You. So maybe light Pokémon World will allow you to catch him if you can beat him in battle. Then you can use Pokémon World and the rest of your team to take on dark Pokémon World. You win, dark Pokémon World goes back to normal so that it can be a "catchable" Pokémon. And everything becomes peaceful again. But that's just a theory. A Game Theory.

I highly doubt it for the main reason that there would have to be like 280 pokemon added to gen 7 which will definitely not happen.

I guess the plot aspect of the theory is possible and would be decent but all the technical stuff like light and dark pokemon seems very unlikely.

Its a good theory but I agree with furret I don't think they will add that many new Pokémon considering they're Pokémon designs are getting on the poor side.

As for the story line its more than likely to be the case, but then it would just be a copy of ruby and sapphire.
One trying to make more land vs One trying to make the ocean bigger. To being one wanting control of light vs One wanting control of darkness. It may as well just be a hack available here if that's the case. But then again its been around 20 years so they could be running out of story lines too, suppose just gonna need to sit tight and wait for the release and possibly waste money buying the dam thing to see lol

TheBWoods15 : Is it really much of a theory when it's just a guess made with no evidence or information? The Game Theorists usually at least try to give some kind of information to back up their theories. However, the part about Team Sun and Team Moon's objectives sounds plausible, if only because that happens in literally almost every mainstream Pokemon game.

Also, if they actually did try to add that many Pokemon, I can imagine that a lot of them would either be clones of other Pokemon or based on really dumb concepts. It's not like you can blame them, though, I guess they have to run out of material to make new Pokemon out of eventually. The game you're describing sounds like it would be great, but it probably won't happen.

I second Furret, I don't see there even being a chance of them adding 280 Pokemon as that is more than has been added over the last 2 generations. Honestly maybe not even half of that considering how little the amount of new Pokemon was generation 6.

The aspects of two evil teams trying to make the world lighter or darker is possible but it is sounding a bit too similar to Team Magma and Aqua in terms of wanting the opposite things and I doubt the evil teams will have the same names as the games themselves in particular with how that hasn't happened in any other game even Sapphire and Ruby. With two legendary Pokemon fighting eachother this theory seems heavily inspired by the generation 3 games, I think if anything they'd try to abstain from making it too similar to R/S/E but there's a possibility I suppose.

Don't think dark Pokemon is going to be a thing since shadow Pokemon were already introduced in Pokemon Colosseum, if they're adding something new I think it's more likely it would be new types, sun and moon types perhaps, or something along those lines. It might be a bit farfetched for those to be types but I wouldn't be surprised to see some sort of new type being added at least.

NovemberJoy : Well if they are running out of ideas then maybe... hopefully not, but I am just thinking that this could be the last generation of Pokémon. So they might squeeze out a whole bunch of new Pokémon to make it an extremely epic generation. Or perhaps the "dark" Pokémon will be counted as individual Pokémon, and only certain ones will be able to become dark. Perhaps ther will be "Nega" evolutions as opposed to Mega evolutions. If it's not the last game generation it might be the last generation with new Pokémon. I actually think...this might be the end of Pokémon. Hence the "end of the world" type plot. Also, I thought perhaps the release of AlphaRuby and OmegaSapphire might be a foreshadowing of what is to come in 2016. Anniversary games, tv shows, etc. Have all been known to include throwbacks to previous installments. The ruby/sapphire-esque story might be a small throwback. It could also have throwbacks to the other games in the story. Perhaps all of the previous enemy "Teams" will appear and they will all be causing trouble in some way. And lastly, I called it a theory just so I could use that catch phrase, I guess it's more of an educated guess, or hypothesis. A Game Hypothesis!

There, is that better?

The idea of it being similar to pokemon sapphire and ruby might be true, but they wouldnt have posted a omega ruby and alpha sapphire if that were the case. Perhaps its closer to the pokemon diamond, pearl, and platinum?  Perhaps closer to either heartgold and soul sliver or maybe pokemon x and y?
I truthfully hope they hire some of their fans who are making awesome pokemon fangames, I hope they sort of like combine everything from all the games from the pokemon walking outside their pokeball with you to pokemon x and y jobs. Maybe we will be able to join the bad guys? Hey who knows it might be two rampaging legendarys. Cant wait till they reveal the plot or some of the pokemon. I have high hopes for this game and i hope they dont shoot it down.