Ston, Uncle, and Ivy continue their quest to find out who or what is affecting the key-stones that give some people the ability to redirect the flow of natural energy. The Source of Truth sends them to a strange world, ruled by the evil Controller. Along the way, they meet an unexpected ally, who is not quite what she seems. They are forced to hunt the deadly beast across a desert filled with peril, while the inhabitants of this terrible world in turn hunt them. Finally, we are introduced to the mysterious Guardians, a race with a hidden past who are the only ones that can restrain an ancient monster.
The action is truly non-stop in this fourth book of the Seven Circles Series.