Kelsie and her little brother Ben are surface dwellers who live in a world ruined by war and greed. Disease has taken their parents, and violence has erupted in their home, the Tent City. To make sure her brother is safe, the malnourished Kelsie must travel to a safe place, a lab that her father had helped build, her father also helped design an AI-capable robot MCHAP that controls the lab. While travelling to the lab, Kelsie nearly dies, but she is saved in the nick of time by Andy, the temporary leader of the Outcast Freedom Troop; a group of freedom fighters fighting for equality between the Surface dwellers and the Bunker dwellers. The Outcast Freedom troop also fights against bands of raiders and slavers that pollute the land. The raiders and slavers earn money by kidnapping surface wanderers like Ben and Kelsie to sell them at the underground human slave and servant market.