Julianne fell in love with her best friend the day he decided to marry someone else.
Julianne Potter, a 27-year-old New York restaurant critic who receives a call from her long-time friend Michael O'Neal. 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 he has fallen in love with and is about to marry Kimberly Wallace, a 20-year-old college student from a wealthy family. This causes Julianne to realize she has always been in love with Michael and cannot stand to see him wed another woman.
Julianne heads to Chicago, intent on sabotaging Michael's wedding.