The premise was actually quite interesting. Dinah's cousin ends up in a coma from self harm. Dinah being bad ass, seeks revenge on the person who caused her cousin to self harm in the first place. Cue main character setting off to boarding school and donning a private school disguise and you have the recipe for intrigue success!
Sounds like a tame kill-bill plot, and the girl actually sounds like she could pull it off. Except once you actually get to the part where Dinah's undercover, it becomes quite apparent that she does not have the intelligence nor the balls to pull it off.
Unfortunately when you figure out the ending before the main character, the rest of the story becomes a battle between 1. giving the book a chance and 2. Mocking everything the main character does because she has no idea.
In this case numero 2 wins by a landslide.
It's not just me being assist at figuring out the ending, its the fact that the ending is so bleeding obvious that it's painful to watch Dinah walk around totally oblivious to it.
If your looking for suspense and badass-ery id look elsewhere.