The land of Aedyn is a paradise beyond all imagining. But when this paradise falls, strangers from another world must be called to fight for the truth. Peter and Julia never suspected that a trip to their grandparents' home in Oxford would contain anything out of the ordinary. But that was before Julia stumbled upon a mysterious garden that shone on moonless nights. It was no accident that she fell into the pool, pulling her brother along with her, but now they're lost in a strange new world and they don't know whom they can trust. Should they believe the mysterious, hooded lords? The ancient monk who appears only when least expected? Or the silent slaves who have a dark secret of their own? In a world inhabited by strange beasts and magical whisperings, two children called from another world will have to discover who they truly are, fighting desperate battles within themselves before they can lead the great revolution.

It has been almost a year since Peter and Julia first visited the land of Aedyn and, faced with the harsh reality of their father’s remarriage and two new horrible stepsiblings, they’re beginning to wonder if it was all a dream. As they run away from home one evening, they fall into a half-frozen river and find themselves back in Aedyn―but this time they’ve accidentally brought along their stepsister Louisa! Aedyn is deserted; the people taken captive and forced to work as slaves at the foot of a volcano on a distant island. As Peter and Julia wonder what has happened to their beloved country, a giant falcon appears and takes them to this island, the very place from which the Lord of Hosts saved his people centuries ago. The three children must find a way to save the prisoners and bring them back to Aedyn, but the earth is trembling and the volcano is starting to smoke. They’re running out of time.

As the volcano’s dark and deadly cloud draws closer, Peter, Julia, and Louisa fight to protect the people of Aedyn, attempting to shelter themselves from the strengthening dark forces. As their enemy closes in, a stranger arrives, claiming to come from the Lord of Hosts to help in their escape to Aedyn and safety. But Louisa doesn’t trust this stranger, and her mistrust leads to further conflict. Can Peter, Julia, and Louisa overcome their disagreements in time to lead the people in the fight for freedom and truth, even when all seems lost?