This book follows The Clockwork Dagger, The Clockwork Crown and The Deepest Poison, all of which I enjoyed. I thought the first book was a steampunk romance. Octavia Leander was the featured character in those books. This book follows the adventures of Octavia's romantic interest Alonzo Garret, younger sister Tatiana and a friend of Octavia and Alonzo, the mechanic Rivka.
Gremlin's are bat like creations of magic and technology. The creator, Mr. Cody, had no interest in the fact that his creatures had developed into thinking animals. His primary purpose seemed to be to create them to fight in his gladiatorial arena.
The two young ladies, Rivka and Tatiana initiate a quest to stop Mr. Cody and emancipate the Gremlins for very diverse reasons. Rivka is very likeable and Tatiana not so much. (I throw that in for a vocal critic of the idea that likeability of characters should not enter into the likeability of books. )
I enjoyed the book and highly recommend it.
This book may have been received free of charge from a publisher or a publicist. That will NEVER have a bearing on my recommendations.