Struggling cartoonist Michael Delaney (Jerry O'Connell) proclaims himself a "professional tomcat" after one of his best friends succumbs to marriage. Now he's up against six buddies, including ultra-smooth player Kyle (Jake Busey), in a betting pool that will leave the "last man standing" unmarried with the jackpot. Fast-forward seven years, when Michael drums up a $51,000 casino tab that he can't pay. Meanwhile the money they wagered and invested has become a sizable pot. He's got a way out of the debt if he can only win the bet, but to do that, he's got to get old friend Natalie (Shannon Elizabeth) to marry Kyle in less than 30 days. However, when Michael begins to fall for Natalie as they stake out her groom-to-be, this dedicated "tomcat" realizes he may win the bet, but lose the woman he loves.