Two and a half years have elapsed since Brad and Simon went through the fireball. Since then they have travelled more than 8000 km from their starting point. Now, captured by Chinese slavers, the two boys are taken from California to China where they find a nation torn apart by civil war. They learn about the power of the Mind, with its creation of illusions, and finally discover the secret of the fireball itself. Faced with a decision which will affect their whole lives, what will they do? Will they return to their own world, or will they venture on into the unknown?