Out of the fire

"It wasn't the kidnapping that ruined Cass Adams's life. It was the letters that came after. The pink envelopes that appear in her car, her locker, her bedroom. Notes from the man she escaped, telling her that he's always there, always watching. The police say there's nothing they can do, and Cass resigns herself to live in fear until she reconnects with three old friends-three girls ready to exact vengeance on those who wronged them"--