What worked: This is an unique take on the whole dead-girl-needs-to-resolve-past-in-order-to-cross-over. In this case the dead try to remember who killed them and take revenge against their murderers. I really liked this twist. The whole karma thing takes on a whole ghostly different meaning.
Echo's story unfolds little by little. She's not the poor dead girl, but has layers to her personality. Not quite 'good', but not all 'bad' either. She longs to be with her boyfriend Andy. There's scenes that paint a vivid portrait of the pain of being torn away before one's time.
There's one dead boy, Cole, that Echo is attracted to. She feels guilty for feeling this way as she tells herself she's still in love with Andy. Cole shows her around Middle House and helps her find her ghostly abilities(each of the dead have one). Along the way their attraction grows.
The other dead kids in the Middle House also have their own stories. Readers get to see one of them find his killer and witness how revenge is taken. I admit, I kind of wanted to see more of these stories. What makes these characters likable is showing their vulnerabilities(yes, it's much more than just being murdered). Even tough ghost Darby has a soft side.
I also like the whole idea of these ghosts having a 'choice' in deciding what they do. The very ending shows this when Echo is given an opportunity to go down one path and the consequences that follow.
Satisfying twist on the whole premise of murdered teens getting revenge. Fast-paced ghostly tale of not only revenge, but redemption.