hm...
a cave is where the player starts, ei?
well, I have this idea to be inserted in LoG's storyline, but you can have it. ;)
here...
the player wakes up in a cave, and has no memory what happened to him nor why he's inside the cave. he recalls he has PKMN but he hasn't. he concludes that someone stole his PKMN from him. then a PKMN cry echoed in the cave. curious enough, he explored the cave even without a PKMN, and then he saw a PKMN(will be the starter). it seems lost so you took care of it and then make your way out from the cave. then once outside, the evil group was talking to each other about the escaped PKMN who entered the cave. they'll see you and will be shocked. they're the ones who stole your PKMN. you also have the PKMN they're looking for, since it's rare in the region. then the town's folk arrives with angry faces and runs after them, and the evil group will make their escape.
sorry if it took me some time to reply back. :P
I'm a salesclerk for the day again~