What is the exposition for lock and key by Sarah Dessen?

Someone Like You is about friendship. It takes place in Lakeview, a "Neighborhood of Friends". There is a new airport just down the street so that is what they're hearing constantly; airplanes taking off and airplanes landing. Halley and Scarlett have been best friends for quite awhile in this book. They're neighbors so they're constantly at each others houses. Halley is the more quiet one who is like Scarletts sidekick and Scarlett is the more popular, outgoing one who everyone knows. There are a lot of barriers in this book that put their friendship to risk but they manage to pull through it.