Fashion photographer Connor Mead (MATTHEW McCONAUGHEY) is at the top of his game. While his assistant, Melanie (NOUREEN DeWULF), handles his scheduling and business affairs, he usually ends up bedding his lingerie models, following the advice of his late Uncle Wayne (MICHAEL DOUGLAS) in terms of getting women in bed but never committing to any of them.
Accordingly, he really isn't in favor of his younger brother, Paul (BRECKIN MEYER), marrying Sandra (LACEY CHABERT), but agrees to be the best man at their wedding. Besides, it allows him to see the various bridesmaids, all but one of which he's previously bedded. That includes Jenny Perotti (JENNIFER GARNER), a physician and the only woman who nearly got him by the heart after knowing each other since they were kids.
She isn't crazy to see Connor, which also holds true for Sandra's father, Sergeant Volkom (ROBERT FORSTER), a Korean War vet who will be officiating at the ceremony. But that also means his sexy ex-wife, Vondra (ANNE ARCHER), will be in attendance, much to the delight of Connor.
He's less thrilled, however, and actually quite shocked, to have an encounter with Uncle Wayne who informs him that he'll be visited by three other ghosts -- from Connor's past, present and future -- who will show him the error of his womanizing ways. Connor thinks his uncle is an alcohol-fueled hallucination until he finds Allison Vandermeersh (EMMA STONE) in his bed. She's the teenager to whom he lost his virginity, and she takes him on a tour of his past behavior, while Mel does the same for his present, and another Ghost (OLGA MALIOUK) does the future bit.
As he contends with that, he must also deal with his resurrected feelings for Jenny who wants little to do with him, especially considering the presence of the handsome and debonair Brad (DANIEL SUNJATA) who's been flown in by the bride for Jenny's enjoyment.