apparently they were on the plane
the plane crashed
they didn't all survive
and now they are being haunted by some mad woman from france on tracy island with sand and trees and dead people on it

ok, but the theroy is this at the moment

the plane didn't crash
they were all abducted by some government type wierdos, brainwashed and probed etc, placed on the island by said mad government scientists and now have a metal link to each other
thats why that bloke can walk and throw knives and shit while the docrot is there to make sure they survive, no one can comb their hair, that sort of business

the plan is that the world is going to kill itself and there are enough of them with enough varied genes to repopulate the world

let me find the link to the post with all this crazy talk on it