I really enjoyed this book. I would say that it is a combination of fantasy and steampunk, with maybe a little science fiction thrown in as well. I'm not sure if replaying the plot will be considered spoilerish, but I'll try. Emily Edwards is a witch living in a small town in California, in the 1870's. She basically practices earth magic. Through a series of unfortunate events, she hooks up with Dreadnought Stanton a warlock from the East Coast. They travel across country and encounter a series of "unfortunate events".
I thought there was wonderful world building in this novel, including the different types of magics. There are references to environmental disasters, prejudices, and unchecked military might (much like today.) I also thought that the Emily and Dreadnought were well fleshed out. Their motivations rang true, and the reasons for the secrets they kept also rang true.
Can't wait to read the next one in the series!