The Aeronaut's Windlass (The Cinder Spires, #1)

by Jim Butcher

Freedom. Grimm realized with a sudden shock of purely mental impact that nothing on earth could convince him to turn down such a deal.

That was a fairly elemental exercise, but doing it a thousand times, all at once, was something of an ambitious effort, more so than any she had successfully used in her practice sessions. Of course, the practice sessions had been embarked upon with the precise goal of providing her with the skill she’d need for a moment just such as this. Goodness, think of what trouble they’d be in if Folly hadn’t practiced.