This is so much more Maggie Stiefvater than Shiver. It's intense and Isabel and Cole are all jagged and wounds and heart. The first part of the story feels more Isabel and Cole than Sam and Grace. Grace's sickness feels like such an afterthought for so much of the book until it's not. Her parents are completely ridiculous and irrational which is as annoying in adult characters as it is in teen characters. I think the most frustrating thing is how long it takes for it all to come to a head. Isabel was completely right that Sam shouldn't have been sliding through life and work at a bookstore, he needed to grow up and pay attention to dying wolves and dying girlfriends and new wolves who needed him to look around and see someone and something other than himself. Which isn't an entirely fair accusation but it's close. By the end I liked Isabel and Cole maybe the best because for all their brokenness they're proactive.
The series pivoted well from Sam and the end of the first book. It still isn't drenched in magic but it held onto enough to work and it opened up doors for the third book well.