Solved - Overnight by Adele Griffin

[sseevers]

I read this book in the past 2 years, I would imagine it was published in the last 10 at the most. It involves a group of girls that have gathered for a sleepover. There is a leader who decides who is in and who is out, and she is sometimes cruel and controlling. The book toggles between each character telling from their viewpoint. At the beginning of the book, one of the girls, who is adopted, wanders off with a strange woman wearing a wig, and is kidnapped. This girl is portrayed as weaker, quieter, meeker, and about to be booted from the group. She is taken to a house where they meet up with the crazy womans boyfriend, until they release her towards the end of the book. The other girls stay at the party, bickering and being mean girls to one another, while their friend is missing. One girls (Who's name could be martha) does things throughout the house and blames others for it. IE: feeds the dog chocolate, puts mothballs throughout the house. I cannot find this book anywhere! It's driving me crazy!