The knock, knock thing got really old really fast. The villain/killer used it most of the time when they had page time. I get that that’s where the name of the book came from but it was extremely annoying.
I liked both Shay and Roman but didn’t really care about them getting together one way or the other. They spend most of the book dancing around each other, so they are only officially together for the last few chapters. Once again Stefan’s in this one. Is the poor guy ever going to catch a break? I get that he knows the most, but why does he always have to be the one helping the newest psychic (newest as in their book and not the one who has just figured it out)? Maddy does show up in this one, so that’s a point in this one’s favor.
It’s probably a good thing that the next book, Rare Find, is the newest one I have for this series at the moment (the next one after that is on hold on my library's overdrive). I like this series but it’s not one that I should be reading back to back like I have been.
I didn’t figure out who the killer/villain was until a page or so before Shay did and they were already fighting that person. I’m really wondering how a literal exploded heart is going to be explained. That’s a nasty image.