Mankind has lost a 300-year war against a genetically enhanced race they created and tortured. Now the descendants of that race - known as the "ghen" - control the planet from advanced underground cities within Hollow Earth. As rising dictator Crecilius Pryme urges his people to annihilate the remaining human population who toil in his factories above ground, a shocking secret is about to be unearthed that will change the lives of the Pryme family forever.