Pain in the ass: Mandy Moore and estranged boyfriend Martin Campbell in Dedication (Photo: The Weinstein Co.)

Women in romantic comedies always choose the fucked-up guy at the end. Often, he's played by John Cusack -- it's a Hollywood law of nature. And the female lead, who's lucky if she gets a five-minute backstory that explains why she might find the main character/total-handful-of-a-boyfriend attractive, is imbued with some sort of magic civilizing powers that set her co-star on the path toward becoming a nicer, happier guy.

The plot of Dedication, which premiered at Sundance and opens Friday in New York, paints a darker, more intellectually driven picture for its mismatched-but-perfect-for-another lovers, but nonetheless sticks to the girl-falls-for-disaster formula. Billy Crudup plays Henry Roth, a neurotic to the max author of children's books whose misanthropy is tempered only by his best friend and illustrator, Rudy (Tom Wilkinson). Aspiring illustrator Lucy (Mandy Moore) is hired by the publishing company to help Henry finish a book in time for its mandated deadline when Rudy dies. The resulting storyline goes like this (what follows can only be considered a spoiler if you've never seen Say Anything, High Fidelity, Knocked Up or any other rom-com): Ugliness, grudging admissions of attraction, a short period of goodness and light, more ugly, followed by a crazy love, leap-of-faith denouement.

To the movie's credit, it is funny and charming and you do end up rooting for Henry, even after he displays all manner of supremely bad behavior. And first-time director Justin Theroux never indulges in a therapy-driven exegesis of his character. We just know that he sometimes has to lie on the floor covered in books, sometimes he sees things, and he really believes that life amounts to an accumulation of suffering. In short, Henry is Russell Crowe from A Beautiful Mind meets Seth Rogen's man-child character in Knocked Up, with a dash of sweet Lloyd Dobler vulnerability -- which is probably his saving grace.

So how and why does Lucy fall in love with him? "Because she grew up in such a crazy sort of way with her mother she's probably better off than most to deal with someone as manic as Billy's character," Moore told The Reeler during a recent press conference in Lower Manhattan. "But initially she was obviously, totally freaked out by him." Lucy's mom, played by the always delightful Dianne Wiest, dishes out suffocating love one moment, withering disapproval the next. The movie's gold standard for batshit crazy, she provides enough character development for Lucy that her attraction to Billy becomes at least believable.

Director Theroux identified the logic of Lucy and Henry as an interpersonal zeitgeist. "In relationships, we bring our damages to the table," he said. "Tom (Wilkinson) has that line where he says, 'We communicate nowadays through damage,' and it's sort of a contemporary vocabulary."

In some ways, the romantic prospects Lucy has to choose from (a formerly cheating and now contrite ex also vies for her attentions) echo the type of scripts Hollywood actresses have to choose from. "It's hard to find good stuff out there, it's so few and far between," said Moore, explaining what drew her to Dedication. "So when you find a project that you want to be a part of, you kind of hang on for dear life. There are very few well-written young women roles and I just loved her sense of self. She's a very patient person, and I just had a lot of admiration for her and her ambition. But the fact that she really did have a strong sense of self, faced with Billy's character and all these crazy obstacles in her life -- she still succeeded."

Although Dedication replaces the dominant romantic themes from the Dobler Era -- when choosing an unlikely love interest was all about breaking class barriers represented by high school cliques -- with a narrative that revels in the myth of the beautiful genius lurking just below he surface of every mentally ill pain in the ass, Moore has a point: Like Dedication, the idea of finding someone who is broken in just the right way offers a much starker, more captivating version of love.