So it's a movie from 2000's, it's a post-apocalyptic movie with zombies in it. I don't remember much but i remember that whole humanity was uneducated, they didn't know anything about "people before them" (us).
In first 30 minutes of movie, they were trapped in a cave, they couldn't get out because zombies were all around that cave. Their quest was to look for some yellow (or some other color) dust, which can cure zombies and reverse them back to humans. They will travel to some city, which is all ruined after whatever happend to people before them. In that city, there was some guy who was something like a king and he has this yellow dust which he didn't want to give to anybody. I know it's not much but please help me, I love that movie! Even if it's not right, still thanks for trying.