Lock and Key — Sarah Dessen

Ruby can take care of herself.

She's used to counting on no one and answering to nobody. But all of that changes when her mother vanishes and Ruby is sent to live with her older sister, Cora. Now Ruby's got her own room in a fabulous new house, she's going to private school, and -- for the first time -- feeling as if she has a future. Plus, there's the adorable and sweet boy next door, Nate. Everything should be perfect. So why is Ruby so wary? And why is Nate keeping her at a distance? Ruby soon comes to realize that sometimes, in order to save yourself, you've got to reach out to someone else.