Plot

Mary Fiore is San Francisco's most successful supplier of romance and glamor. She knows all the tricks. She knows all the rules. But then she breaks the most important rule of all: she falls in love with the groom.

Mary Fiore is the wedding planner. She's ambitious, hard-working, extremely organized, and she knows exactly what to do and say to make any wedding a spectacular event. Bt when Mary falls (literally) for a handsome doctor her busy yet uncomplicated life is turned upside down - he's the groom in the biggest wedding of her career! Will she help him walk down the aisle with his internet tycoon girlfriend, or will Mary finally get to be the bride herself? When it comes to love, you can never plan what's going to happen.—Ron Borgstedt <ronborgstedt@sbcglobal.net>

After planning and coordinating another successful wedding ceremony, San Francisco wedding planner Mary (Jennifer Lopez) is re-introduced to childhood acquaintance Massimo (Justin Chambers) by her father (Alex Rocco) who wants the two of them to marry. Mary, however, is not impressed and instead remains focused on her ambition to become a partner at the wedding company she works for. As a way to persuade her boss, Geri (Kathy Najimy), to accept her as a partner, Mary pursues and is hired by catering heiress, Fran Donolly (Bridgette Wilson) to plan her society wedding to long term boyfriend 'Eddie'. While on the phone reporting her success Mary's shoe heel gets stuck in a manhole cover. While she attempts to free herself a taxi collides with a dumpster and it comes hurtling towards her. A man standing nearby rushes in and pulls her away just before the dumpster crashes.

She later wakes up in hospital and the man who saved her is revealed to be the local pediatrician, Steve Edison (Matthew McConaughey). When Mary's friend and colleague Penny (Judy Greer) arrives she persuades Steve to attend an outdoor movie screening with them at the park, only to make up an excuse to leave the pair alone. At the movie Mary and Steve dance but as they are about to kiss a heavy downpour forces them to run for cover.

A few days later Mary and Fran are at another of Mary's weddings and Fran teases her for her dreamy look before Mary tells her about her movie date. Later on Mary is attending a dance lesson with another of her clients. Fran is also attending and introduces Mary to her fiance 'Eddie' who turns out to be Steve. Mary angrily rebukes him for leading her on and going behind Fran's back. Mary is left wondering whether she should continue to plan Fran and Steve's wedding, while Steve is left wondering whether his chemistry with Mary is a sign that he shouldn't be marrying Fran. Penny persuades Mary that her career is more important than whatever attraction she might have felt for Steve.

When they arrive at a potential wedding venue in Napa Valley, Massimo appears and, to Mary's confusion and horror, introduces himself as her fiance. Later when the four of them, along with Fran's parents, are riding on horseback through the estate, Mrs Donolly's singing frightens Mary's horse and it rushes off with a terrified Mary clinging on. Steve instantly gallops after Mary and rescues her from the out of control horse. When the pair are alone he bitterly rebukes her for condemning his actions when she was also engaged.

At home, Mary's father excitedly talks about her upcoming wedding, only for her to reveal that she and Massimo are not engaged before scolding her father for trying to arrange her marriage. Her father then reveals that his wedding with her mother, which Mary had always seen as the perfect marriage, was actually arranged and only became a loving relationship months later, leaving Mary feeling very confused. Mary, Fran and Steve visit another potential wedding venue. Differences in opinion between the couple begin to emerge but Steve agrees with whatever makes Fran happy. Fran reveals she is going on a week-long business trip, leaving Mary and Steve to continue with the wedding preparations. The pair apologize for their angry words. While looking for flowers they run into Keith and Wendy. Mary reveals that Keith was her fiance, Wendy was his high-school girlfriend and during their rehearsal dinner she found them making out in her car.

That night a drunk Mary laments over Keith being married and expecting a baby while she is still alone and miserable. Steve comforts her and insists that Keith was a fool to pick Wendy over her. He then leaves but quickly returns and confesses that he has feelings for Mary. She sadly replies that she respects Fran too much to let anything happen between them and sends Steve away.

Fran returns early from her trip and comes to speak with Mary. Mary fears that Steve has revealed his feelings for her but instead Fran reveals she doesn't know if she is in love with Steve anymore. Ignoring her heart, Mary persuades Fran to go ahead with the wedding. At a birthday party they are both attending, Massimo offers Mary a heartfelt proposal and after a little hesitation she finally agrees to marry him. The two couples prepare for their weddings. When the day arrives Mary leaves Penny to coordinate the Donolly wedding before she goes to the town hall to marry Massimo. Before the wedding starts, Steve takes Fran for a walk and asks her if they're doing the right thing. Fran eventually admits that she doesn't want to get married. The pair part as friends and Fran leaves to go on their honeymoon alone. Penny reveals Mary's plans to Steve and he rushes off to stop her.

At the town hall, Massimo and Mary prepare to marry but her father stops the ceremony, realizing that the wedding is what he wants for her and not what she wants. Mary, who has given up on true love, insists that life isn't a fairy-tale and marrying Massimo is the right thing to do. Steve arrives to find Mary's father and Massimo outside. Massimo reveals that he couldn't go ahead with the wedding knowing that Mary was not in love with him and actually in love with Steve. Steve reveals his feelings to Mary's father, who tells him to go and get her. Steve and Massimo ride off on Massimo's scooter to the park where another outdoor movie is starting. Steve finds Mary, asks her to dance and the pair finally kiss.