Rise and Fall — Kaye Draper

Drawn into his sister's mischief, Henrick helps her to elope with her human lover -- a man of an outcast race, who is little more than a slave. But Henrick soon finds himself swept up in a taboo love affair of his own -- and race and social class are the least of his problems. While attempting save the lives of his soulmate and his sister from the hands of slavers and air pirates, Henrick finds himself embroiled in the machinations of a madman -- a Shifter bent on framing Henrick and Win's parents for the murder and starting a world war. Now he must journey into the desert wastes and through the infamous Floating City to save the ones he loves.