The worlds on either side of the mirror are about to collide. And there’s nothing Jacob can do to stop them. After a perilous encounter with an Alder Elf - an immortal, trickturning creature to whom he owes a great debt - Jacob must journey back into the enchanted Mirrorworld once again. Together with Fox, his beautiful shapeshifting friend, Jacob has no choice but to follow his brother on the trail of the Dark Fairy, who has fled deep into the East: to a land of folklore, Cossacks, spies, timeeating witches and flying carpets. But what exactly is the Dark One running from? Could it be the same danger that threatens Jacob and Fox?