After chasing the monster that kidnapped their mother, Emily and Navin find themselves in a magical world of man-eating demons and shadowy enemies, where they must learn to control an amulet given to them by their grandfather.

This electrifying conclusion to the #1 New York times best-selling series follows Emily as she travels to Typhon to confront the fraud who has seized power in the absence of a king and must rely on new friends and old enemies to survive the threat of darkness.

After the tragic death of their father, Emily and Navin move with their mother to the home of her deceased great-grandfather, but the strange house proves to be dangerous. Before long, a sinister creature lures the kids' mom through a door in the basement. Em and Navin, desperate not to lose her, follow her into an underground world inhabited by demons, robots, and talking animals.

Emily and her brother Navin head for Kanalis to find an antidote for the poison that is killing their mother.