An African tribe called the Ik throws their children out of their homes once they turn 3. They are left to fend for themselves with no help from their parents at all, and to survive, form groups with others their age. These groups only last a few years, and every so often the individual will join a completely different group.
Real world scientists have accidentally opened a tear in the fabric of reality, transporting their laboratory into the game world. Unable to repair and/or refuel their equipment in this (to their minds) primitive world they are now trapped.