Jacob, Fox and Will are on the trail of the Dark Fairy, and this time their journey beyond the Mirrors takes them deep into the East - into the realm of Russian folklore, of Baba Yagas, Cossacks, spies, and a tsar who turns up to audiences in the company of a bear...But someone else is in control: one of the Alder Elves, Immortals at home on both sides of the Mirrors, has not forgotten the promise Jacob made him in a Bluebeard's labyrinth. He teaches the three of them more about himself and his kind than they ever wanted to know, as the worlds either side of the Mirrors begin to collide.