In a remote, heavily wooded area near the Berkshires of Massachusetts, Rachel Lorant died on her birthday. But she didn't die alone. That night, her four sorority sisters make a solemn, trembling pledge. They will never reveal what has just happened in those woods - ever. Instead, they will take their terrible secret to their graves...Now, ten years later, their secret is coming back to haunt them as each receives a card in the mail from Rachel: "Happy Birthday to Me. xoxo R." It's clear that someone knows what happened that night. Someone is stalking them and sending mysterious, chilling gifts that only they can understand - deadly warnings of what is to come. For the sins of the past have come back with a vengeance, and a killer will see that they all pay in blood...Brynn Costello has never felt such pure fear. She didn't want any part in what happened so long ago, but now, the mother of two will do anything to stay alive and protect her family - even if it means matching wits with a killer she can't see...a twisted psychopath who is closer than she thinks and who is saving her death for last...