You leave your village to seek your fortune or whatever. While you’re away the village commits a great sin. That sin turns them into monsters, and Jareth appears to set things right. You enter a dungeon thinking you are rescuing your friends and family. Instead you are killing them. You fight your way through the dungeon trying to rescue them. When you reach a point you realize that your village created this sin and they got turned into monsters. Then you have this question of whether you continue killing the monsters or you incapacitate the monsters (parents need to be central to the sin). Then if you incapacitate monsters you fight jareth if you kill the monsters you fight your parents