Martin may have managed to get his sister, Cassie, to safety, but his nightmare is far from over. Cassie's school has been ransacked and all the children are missing, and with the totalitarian regime still in place, constantly watching, Martin is finding it hard to uncover the answers he needs.

But Martin will do anything to keep Cassie safe… Accompanied by his AllDog, Chip, he starts to excavate the burned-out shell of an ancient metropolis, and discovers that the heart of the government's central power is closer to Martin than he ever could have imagined…