What happens when a party game turns deadly? For her 21st birthday, Abbie Reed's friends throw her a surprise party and plan an outrageous game of 21 Dares. The rules are simple: Abbie must follow each dare to the letter as they pop-up on her phone--each one sent as a text message from a secret guest. Starting off funny, if not a little humiliating, the dares send Abbie and her friends across her college campus and through downtown Tampa. But the closer they get to the mystery man behind the text messages, the more deadly the dares become. Harboring a vendetta against Abbie, the mysterious guest won't stop until she pays. Now, it's up to Abbie to figure out who he is and what he wants, before her 21st birthday becomes her last.