Mary Fiore (JENNIFER LOPEZ) is a busy, professional wedding planner who, despite her success at her occupation, has never been married herself. That's concerned her widowed father, Salvatore (ALEX ROCCO), who's decided to fix her up with Massimo (JUSTIN CHAMBERS), a childhood Italian acquaintance of hers who's best remembered for eating mud as a boy. Pleasant, but seemingly somewhat dimwitted, Massimo mistakenly believes that he's now engaged to Mary who obviously wants nothing to do with him.
Besides, she has bigger fish to fry, especially when she hears that ultra successful Internet entrepreneur Fran Donolly (BRIDGETTE WILSON-SAMPRAS) has announced her recent engagement. Knowing she brings in more money than the rest of her firm's planners, Mary convinces her boss, Geri (KATHY NAJIMY), to promote her to partner if she successfully plans and executes Fran's wedding.
To top it off, a charming and handsome pediatrician has just saved her life, and the romantic sparks immediately fly between them, resulting in a near kiss on a subsequent, unofficial date. Things couldn't seem to be any better until she realizes that the doctor is Steve Edison (MATTHEW MCCONAUGHEY), Fran's fiancé. Although she doesn't let the bride to be in on this startling revelation, Mary is furious with Steve, but realizes she must play it cool and keep the wedding on track so that she can get her promotion.
As the three of them plan the wedding along with her assistant, Penny (JUDY GREER) and Fran's parents (JOANNA GLEASON and CHARLES KIMBROUGH), Mary must sort out her feelings for Steve while he does the same regarding her and his pending marriage to Fran.