The Iron Angel: The Third Book of Lowmoor (The Book of Lowmoor series)

Desperate to stop the wicked Querne Rasp from collecting the final crystal she needs to complete her collection, Jewel and Thorn find themselves drawn deep into the inner workings of an ancient and sinister church. Along the way they fight ice spiders and other obstacles, and as always Racky Jagger is determined to thwart their plans. But when Racky shares a revelation with Thorn, both of their lives change irrevocably.