When a greedy scientist and a power-seeking corporation created the guardian program, an experiment with cyber-human hybrids programmed to train children to be perfect citizens, the prototypes became self-aware, developing personalities that distort their mission and threaten the entire Dome. More powerful than their creators, the prototypes test their abilities in a battle of wills that drives Gayle and her eight-year-old son, David, into hiding in the perilous slums of the Downs, which she desperately tried to escape by volunteering for the program. The hybrids ultimately turn against each other, using Gayle and David as pawns in a game that shows the dark side of the wealthy Uptown world and the revolutionary power of the Dome underclass.