This book takes a different approach to steampunk than I'm used to by combining it with paranormal romance. The romantic passages are ostensibly confined to Victorian sensibilities, but I suspect that even the details divulged in passing would only be spoken of in hushed tones if placed in the actual 19th Century. Much of the plot revolves around the burgeoning attraction between Alexia, a spinster at the shameful age of 25, and Lord Connal Maccon, an immortal werewolf. The more standard topics of technology, change, and mad science serve as the structure their interactions build upon. Carriger puts a different spin on the causes of immortality. As normal, werewolves are still weakened by the sun and controlled by the full moon, and vampires cannot abide the sun. However, their status comes from an excess of soul. Alexia has the opposite condition, a complete lack of soul, and serves as a new kind of unnatural human that can remove the powers of any supernatural she touches. I may have missed the explanation in the book, but I'm still not sure what soul means in these contexts. As best I can figure it correlates to how emotional, passionate, or creative someone is with Alexia being described in contrast as very practical and not given to flights of fancy or displays of emotion. 
 I enjoyed the plot and the developing relationship between the protagonists. The two styles played off each other very well. The book certainly does not take itself seriously and is given to much tongue in cheek humor to keep everything from becoming too dark and serious. Many of the supporting characters border on caricatures to support the more humorous mood.