Lock and Key by Sarah Dessen

I've read a lot of Dessen's books, but out of all her many books, this I have to say, is the best one.
Lock and Key is about a teenage girl named Ruby who lived in an old yellow house because her mother mysteriously disappeared from Ruby, so poor girl she has no choice but to live alone. Unfortunately for Ruby a social worker visits the old yellow house and asks Ruby why she was living alone.
Ruby knows the jig is up and goes to live with her newly married elder sister Cora and her rich entrepreneur husband Jamie. Although Ruby now lives in a luxurious house, gets whatever she wants, and goes to a rich kid's private school, she still can't seem to be grateful for everyone and everything around her. Cora thinks Ruby is having some problems fitting into her new school, but unfortunately it's not that simple.
To find out what's the real reason Ruby can't find her happiness, it might be good to read this book.
Also, don't try and do it the easy way and search on Google what happens next. Nothing can beat the joy of actually reading this book.