I read this book a while back, so my memory of it has dimmed a bit.
I really love the heck out of both Benna Yovanoff and Maggie Stiefvater. Tessa Gratton is the third member of their writer's group, the Merry Sisters of Fate.
They have published one joint book of stories, The Curiosities, that is really quite wonderful. The really neat thing about it are the notations and discussion between the three writers that litter the pages. This is a book to be owned in print, because something is definitely lost in the e-version.
All three of them are very talented writers. If I was forced to rank them in order, though, I think that Tessa Gratton is my least favorite of the three. Although not because she is not talented. But the other two, oh, my word, their words. Maggie Stiefvater is one of my favorite wordsmiths, and Brenna Yovanoffs write stand-alones that owe a debt to the likes of Shirley Jackson - deliciously creepy and intelligent.
This was my first book by Tessa Gratton, and I liked it, but it wasn't anything particularly special. It was enjoyable enough for me to read the companion volume, which I actually liked better. Review on that one forthcoming.