I don't want to say I "love" anything here because it's an emotion that feels wrong when it comes to this book, well, actually, I can say I love the writing. That's okay.
With such a challenge for today this is a bit of a downer entry...
I've read a lot of books where the protagonist was a victim of abuse and while it's true that there is no one way of how a victim would act, this is one that I hadn't found before in any of my previous readings.
Usually books with a protagonist who is an abuse victim go a bit like this: protagonist suffers, protagonists meets boy/girl who convinces protagonist it's okay to trust again, protagonist goes through emotional catharsis, protagonist and boy/girl HEA.
Summers explored an issue in dire need of attention: when the abuse has left the victim unable to form emotional connections to others.
Those other books, I'm not saying they're wrong, or not as good - as I said and it bears repeating, there isn't a unified experience in these issues. But in those other books the protagonist has at least one friend, an acquaintance, someone they can trust. They feel something for other people.
But there are cases where this very primal human act of bonding with another human being has been all but obliterated - when they don't make new friends because it'll just be worse in the long run, because the abuser is so controlling that other relationships are forbidden.
Sloane (the protagonist), has a friend, a confidant, someone she loves desperately because she fulfils all those roles she wasn't allowed to have: her sister. But her sister left. She left Sloane alone with their father, the abuser.
This is brutal for the reader: one the one hand, you're appalled that she would leave her own sister alone in such circumstances. But on the other hand, you can't blame her for escaping such a terrible situation.
All the zombie stuff... it's perfect in the way it serves to highlight how alien, how empty Sloane is when compared to her classmates. How much closer she is, in emotional terms, to the zombies roaming outside.
So yeah, if you're looking for something to make you feel miserable, this is it.
But it's so good!!!