For Zach, breaking up is the easy part - he's already done it a dozen times. But when his childhood crush, Abbey, decides to move to New York, Zach realizes that he's about to lose the only girl he's ever truly loved. Now, with the help of his best friend, Bleckman, Zach has just three days to question all 12 of his ex-girlfriends and find out just exactly what went wrong. This time he just has to get it right - before the love of his life becomes the unlucky number 13.