Ever since the floods came and washed the world away, survivors have been desperate to win a place on X-Isle, the island where life is rumored to be easier than on what's left of the mainland. Only young boys stand a chance of getting in, the smaller and lighter the better. Baz and Ray are two of the lucky few to be chosen, but soon they discover that X-Isle is a far cry from paradise. Ruled by Preacher John, a dangerous religious fanatic, it's a violent, unpredictable place, where terrible things can happen at any moment. The boys hatch an extraordinary plan to order to protect themselves - the construction of a mighty weapon of defense. But can they complete this weapon in time, and are they really prepared to use it to secure their freedom?