The Wonder Engine - T. Kingfisher

Pull three people out of prison--a disgraced paladin, a convicted forger, and a heartless assassin. Give them weapons, carnivorous tattoos, and each other. Point them at the enemy.

What could possibly go wrong?

In the sequel to CLOCKWORK BOYS, Slate, Brenner, Caliban and Learned Edmund have arrived in Anuket City, the source of the mysterious Clockwork Boys. But the secrets they're keeping could well destroy them, before the city even gets the chance...