Bone series, book 8.

The Bones, Thorn, and Gran'ma Rose have reached Atheia and look for supporters to battle the Lord of the Locusts. Unfortunately, Atheia's new leader views the royal family as heretics and plans to kill them the first chance he gets.

Phoney, meanwhile, is convinced that there is treasure to be found and sets out to find it.

And then Briar and her army attack the city...