Garth Nix is back with the sixth explosive title in his gripping fantasy series, The Keys to the Kingdom.On the Sixth Day, there was SorceryArthur Penhaligon has wrested five of the Keys from their immortal guardians, the Trustees of the Will. But gaining the Sixth Key poses a greater challenge than any he has ever faced before. Superior Saturday is not just one of the Trustees, she is also the oldest Denizen and the most powerful and knowledgeable sorcerer within the House. She has tens of thousands of sorcerers at her command - and she has been preparing her forces all along for the Will's escape and the activities of the Rightful Heir. Everything is all just part of a greater plan she has been hatching for ten thousand years.As Saturday's schemes become evident, Arthur is beset on all sides. Nothing is eroding the House, and only the power of the Keys can hold back the tide of destruction. His mother is still missing. His home city is under attack. His allies are unreliable. He can't even get into the apparently impregnable Upper House and even if he does, finding the Sixth Part of the Will and gaining the Sixth Key might not be enough to counter Saturday's sorcerous hordes or stop her bid for ultimate power.