Bladers around the world are competing in a survival battle on an isolated island. The main 6 are all there, well most of them (Twilight disappeared in a factory accident and was never seen again)
1000 Bladers enter, 1 survives.

P.S: In this story almost nobody has meet each other yet (Twilight and Sunset were childhood friends. While Rainbow Dash and Fluttershy are still friends).