Engines of the Apocalypse — Mike Wild

Giant dwarven sirens rise from the ground and, all across Twilight, magic stops. Blamed for the emergence of these machines Kali Hooper faces execution until a mysterious stranger offers her a deal. In order to keep her life, Kali is to help find the tyrannical head of the Final Faith, Katherine Makennon. Kali joins old enemies and unexpected allies in an epic quest that pits her against the dark machinations of the Pale Lord and reveals secrets not even she could have guessed at!