The humans are weak and vulnerable. Soon the beasts that share their stone-age world will kill and eat them. To save his tribe, Stopmouth must make his way to the Roof, the mysterious hi-tech world above the surface. But the Roof has its own problems. The nano technology that controls everything from the environment to the human body is collapsing. A virus has already destroyed the Upstairs, sending millions of refugees to seek shelter below. And now a rebellion against the Commission, organized by the fanatical Religious, is about to break. Hunted by the Commission's Elite Agents through the overcrowded, decaying city of the future, Stopmouth must succeed in a hunt of his own: to find the secret power hidden in the Roof's computerized brain, and return to his people before it is too late. Peadar O Guilin has followed his extraordinary debut The Inferior with an equally original and pulse-racing sequel in which human primitivism collides with futuristic technology.