its a little diffacult to explain. you start out as either claire or sam (who later becomes eric, becuase it turns out eric is sams twin) and after you beat the game the first time you can be either james or this jappanesse girl whose name i cant recall at this moment. each charter has a diffrent take on the story, for instance, if you play as claire eric or james you meet the last girl after her plane crashes and you find her unconciuss, but if you play as her, you dont met them like that, you have to find them on the island.also, if you play as james or the last girl, you never meet the real sam