Lucy (Kate Hudson) meets an extremely shy young man named Adam (Stuart Townsend) and the two quickly fall in love. Eventually Lucy proposes to him and he accepts. Little does she know, however, that Adam has seduced virtually every member of her family, and each family member sees him in a totally different light than the others. At the end of the movie, Adam reveals that he is only giving all of them what they need to be happy in life, and he needs Lucy to be happy himself. Lucy, who had a last fling with one of her exes before the wedding, decides she can't go through with her wedding. Adam finds her and convinces her its ok to have secrets, but that their married life will be a new beginning for them all, free of past mistakes. Everyone ends up happier than they started.
Laura (Frances O'Connor) - The middle sister who falls for Adam's dark and brooding side. She is an uptight academic obsessed with researching female oppression. After being seduced by Adam, she realizes that she loves living freely and embraces her sexual liberation. She becomes happier, both personally and professionally. She ends up writing one of the most exciting literary theses in school history and ends up dating her advisor who is perfect for her.
David (Alan Maher) - He is Laura's brother and idolizes Adam's womanizing abilities. David is unable to get his long-term girlfriend to sleep with him, so Adam invites himself over and seduces both David and his girlfriend (though he doesn't sleep with either of them, he only turns them on). When he leaves, David and his girlfriend are so horny that they finally sleep together and the sex is great.
Alice (Charlotte Bradley) - She is Lucy's oldest sister and is attracted to his youthful vigor. Alice is having depressed about growing old and her marriage is crumbling. She eventually succumbs to Adam's charms, thrilled to find that she is still attractive and good in bed. She ends up hugging her husband and child after Lucy and Adam's wedding, and looks much happier than when the movie began.