I really enjoyed this, a lot. Kami is a fun character, as a Nancy Drew fan, I really enjoyed her characterization. The mystery and the world building is very good, though I kept having to remind myself that it wasn't set in the 50s/60s, because it really gave off a "retro" vibe. I think some readers might find that frustrating, having Kami seem sort of out of time or of the past vs other characters who were much more rooted in present time/modern era. I thought it worked for the book, as Sorry in the Vale is somewhat out of time as well.
I would certainly recommend to any Nancy Drew or girl detective fans, though the cliffhanger at the end...not cool Sarah Rees Brennan! So glad the sequel is out in the next week, but am fairly certain that book 2 will also end on a monstrous cliffhanger, so be warned!