A fast-paced sci-fi with intriguing technology where merchant airships hover above a crater where slaves are forced to work in mines. A boy, Zephyr, aims to escape this slave world of cracking rocks, is initiated into an elite gang of thieves and learns a technique to hoist himself up the many levels of the crater and in so doing neglects his duty to his friends and gang mates.
Bacchus, an airship captain, is hired to rescue a girl from Crater and by coincidence enlists Zephyr to help. Turns out both Bacchus and Zephyr are more than they appear to be as they escape and are chased into the world above.
There are interesting side characters, like the Tinker and his granddaughter, who play essential parts in the technology.
What marred the story somewhat for me were the frequent typos, especially in the latter stages of the book which appeared rushed as though the author wanted to finish the plot but didn't have time to edit his style.