Lol. Red hasn't checked it yet.
Well, mainly its about the legendary pokemon and Arceus.
As a character, you are a human from the human world who is confronted by a pokemon. Kidnapped or not, they end up taking you to their world, and you have a decision between fighting Arceus or protecting him.
In the world they live in there's no humans nor trainers, but they need you to help them, and harness their power. It'll be better explained once you see it.
You get to choose which pokemon confronts you, and what side you want to be on.