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?

During a meteor shower above the town of Zion Falls, Pablo and his friends discover that some monsters are real when they are attacked by hungry trolls.

The Wing Warriors work for the Library of Doom, circling the world in a floating fortress as they search for dangerous books. But, when a new book is brought aboard, monsters come flying after it. Can the Warriors and the mighty Librarian keep the gargoyle horde from getting their claws on the book's deadly pages? Uncover hidden dangers and dark mysteries with Secrets of the Library of Doom, a page-turning chapter book series from bestselling author...

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.