While Lily's voice rings through loud and clear in the novel as a kick-ass heroine who makes a lot of mistakes, but takes no prisoners, Mel's voice was a little more difficult to get a handle on. It was rendered effectively by the author but I wasn't sure how much it actually contributed to the story. It seemed pretty peripheral. I got the sense it was important to hear Mel speak in this book because her character apparently changes a lot in the second book (I won't give away any spoilers) and it's probably necessary to plant the groundwork in the first book so we can appreciate the change in the second. Carter is a great character because his loyalties are so divided and he's trying to do the right thing in circumstances where there are no easy choices - and the poor guy is battling his attraction to Lily the whole way through the book for reasons that become apparent but I won't go into it here because I don't want to give anything away.
This is not high-level literature by any stretch of the imagination. It's action and thrills all the way. I was a little concerned about its suitability for younger audiences when I read on the cover blurb that it was billed as a cross between Resident Evil and The Hunger Games. But it's really not that bad. There's not that much blood and gore on the pages so I don't think it should be off-putting for any parents who want their children to have a good fun read. And there's no explicit sexual content either. So don't be deterred by the advertising material. It's pretty accessible and entertaining for younger readers all around.