My game: Sonic the Hedgehog: World's end
prologue: Sonic is lying around on a tree in the green hill zone, when suddenly Silver happens to walk by. Sonic thinks to himself, "This is strange".
So Sonic calls out to Silver, "Yo! Whats up Silver?!"
"Sonic!? What are you doing here?"
"Just chillin, how about you something amiss in the future, or are just droppin by to say hello?"
"The future?"
"Yeah, didn't you say you were from the future of this time?
"Oh, no!"
"Whats up?"
"I'm sorry Sonic, I have to go!"
So Silver runs off into the distance in a hurry but before he can get too far, the Egg Viper randomly appears in front of Sonic.
"Huh?" This is strange Doctor Eggman says inside of the machine.
Sonic takes quick notice and easily defeats the Egg Viper, Afterwards Sonic says "Running out of ideas Eggy?"
"What do you mean? This is the first time I've used this machine!", Eggman responds.
Suddenly, black holes appear all around Sonic; so he races forward in search of Tails, so they can figure out what is going on.
It turns out that using the chaos emeralds as many times as our heroes have, has caused the world to become dimensionally unsable, now Sonic and friends must work together in order to save not just the world, but reality it's self.
Playable Characters: Sonic, Silver, Tails, Eggman, and every other sonic character.
And well there's too much to talk about just post a question if you wanna know more.