The young heroes have escaped from the underground kingdom of the trolls, but a final battle still awaits them at Zion Falls, where the trolls are controlling the people's minds and using them to attack the children of the stars--will any of them survive?

On the morning after the troll attack, Pablo and his friends wake to find that a dark tower is rising from the ground, and that only they can stop the army of evil that is about to invade Zion Falls.