It has been fifteen years since Billy and Bonnie Bannister helped repel the demonic assault on Heaven. Now they and Ashley Foley sit in a maximum security prison where the authorities conduct experiments on them to learn the secrets of long life. Earlier, the world's acceptance of dragonkind crumbled, and the Enforcers took the infant twins born to Billy and Bonnie and stole Excalibur, hoping to develop a weapon to battle the dragons that are sure...

To stop the coming apocalypse, Matt and his mother Bonnie must travel to seven destinations, each containing a door that opens onto a unique brand of evil that is designed to weaken Bonnie's soul-healing song and bring God's wrath upon the Earth. Opening the final door could doom the planet, yet the remedy they seek is behind that very door.