I’ll start by saying that I love how Nethercott utilized Eastern European myth and blended it really nicely into an urban fantasy setting.
However— so much of this story takes place in the past. I really just wanted to know what the heck was happening in the present, and usually it was nothing but derping around in Thistlefoot. The prose is beautiful at times, but extensive to the point of annoyance. Full on chapters of just ambiance with nothing really happening. 
To that point, I found the driving action nearly nonexistent, the threat talked up a lot but under-demonstrated, and the characters were written as angsty teens masquerading as adults. Found it really hard to get into and especially to *stay* into.