Spell Bound fits seamlessly into the wider series but it can't be read as a stand-alone. If you haven't read all the other books in the series, including the short stories, there will be plenty of references you are going to miss. 
 The mystery and the style of writing is pretty consistent with Kelly Armstrong's usual standard although I would classify "Spell Bound" and "Waking the Witch" more as YA urban fantasy than an adult paranormal series. If you like Armstrong's other "Women of the Otherworld" book series, you will probably enjoy this one since it is very much in the same spirit. 
 We have watched Savannah grow from a young teenager and suffer through various traumatic experiences along the way, but she is no longer a teenager. Savannah is now a gorgeous twenty-one year old witch/sorcerer/granddaughter of a Demon Lord hybrid. Savannah's world had gotten a good hard shake at the end of the "Waking the Witch" when she lost her powers. Unfortunately, for the most part Savannah turns into a selfish, annoying, reckless, bitchy brat and at times a bully because of her insecurities. Even Hope didn't frustrate me as much in her own stories. Except for Kayla, Savannah is pretty much lacking in empathy. Leave it up to Clay to finally tell her to grow up, something I wish Paige did years ago. That is when we finally see a small shift in her attitude. 
 I enjoyed all the cameos. I wish we saw more of her parents and Sean but was pacified with getting Bryce.