Flight of the Kharadron Warhammer Adventures: Realm Quest Series, Book 4

On a quest to find their missing master, Alish, Kiri, Thanis, Kaspar and Elio are captured by the sky-faring Kharadron. They are taken to a shadowy city above the clouds, a place of marvels, of airships and flying wonders! Alish and the others are offered their freedom but only if they have nerve enough to steal a heavily guarded treasure first.