The allies are trapped on Mistmurk Mountain and the God-Emperor guards every way of escape. There's only one chance for freedom: for demure little Maelys to confess to a crime she has not committed, though if she does it will turn all her friends against her. And even if they can flee through the perilous shadow realm, the God-Emporer's armies will hunt them to the ends of the world. Nish, Flydd and Maelys have no choice but to venture to the Tower of a Thousand Steps, on the frozen Isle of Noom. There they must seek aid from the implacable sorcerer who controlled the world for an unknown but terrible purpose for one hundred and fifty years - the Numinator. But on that tragic journey they will uncover a greater and more deadly secret, a folly that has been shaping life and death in the Three Worlds for more than three thousand years, and now threatens to consume them all.