We all know that children can be very mean as depicted in this 2008 film.
When a family comes up from Florida to live in N.Y., they stay temporarily with a wealthy family as both the men are friends from their school days. Unfortunately, our New Yorker has a daughter by the name of Massey. She is as stuck up as they come and she begins to make life miserable for our Floridian girl named Claire.
Massey, as selfish and snobbish as they come, belongs to a clique with 3 other girls. Everyone wants to be in their group but they operate a closed agency shop.
Claire is able to finally get even with the nastiness they have shown to her by sending them messages on the internet, where the girls will grow to detest Massey and accept Claire. Clair becomes like a Massey until the latter realizes what she has done and alerted her former friends. Then it's back to square 1 for Claire.
The movie just brings up the idea of how difficult teenagers can be as they're growing up. Those hormones are sure active!