A strange story. It's entertaining, to be sure, just different. :) First and foremost, I liked Maggie. It was incredibly refreshing to see a teen girl who isn't constantly questioning herself and never pines to be like the popular girls. I loved that.
I thought this was going to be something like a YA version of Dexter, but it's not. Not really. Maggie does kill people, because the voice in her head compels her to do so. When this voice manifests, it causes her physical pain, so she feels she has to do what he says just to get the pain to stop. I was very interested to see how her story was going to pan out.
I tried to write this review without spoilers, but found it wasn't really possible. So there are spoilers below, some big ones.
Things get inconsistent as the story progresses. She goes along with the voice when the targets are low-life abusers, but she refuses to comply when the voice tells her to throw a baby down the stairs. Or when he tells her to run over a bicyclist. There were no consequences to either incident. So why didn't she start resisting more? Then, at the end when she tells the voice his ideas are stupid, he gets weaker. Why didn't this happen sooner when she'd successfully disobeyed?
The transitions were rough, too. One minute, summer is starting, then school starts three pages later. The worst was when Harry dies. We went from he's-not-feeling-well to his funeral, and gloss over the fact that Maggie tried to kill herself afterward. We learn that bit in a whispered conversation between her therapist and her mother, but we never get to experience Maggie's grief firsthand. I'm not sure why. This book doesn't shy away from darkness (she *kills* people), so I don't know why we didn't get to be in Maggie's head when she decides she doesn't want to be in this world any longer.
There is no building tension, either. The story feels pretty even throughout. Maggie kills people. She still kills people. Her stepfather dies and she's nearly destroyed from the grief. She goes back home with plans to burn down her friend's house, after giving the voice in her head some sass. There's no beginning, middle, or ending. The fact that she's talking back to the voice in her head is a good thing, but it's not enough. I wanted to feel tension building throughout the story, and then be rewarded with an amazing conclusion that knocked my socks off. I think this story could have done it, but, sadly, it didn't.