Julianne Potter (Julia Roberts), a 27-year-old New York City restaurant critic, receives a call from her lifelong friend Michael O'Neal (Dermot Mulroney). In college, the two made an agreement that if neither of them were married by the time they turned 28, they would marry each other. Three weeks before her 28th birthday, Michael tells her that in four days, he will marry Kimmy Wallace (Cameron Diaz), a 20-year-old University of Chicago student from a Upper class family.