Stop me if you’ve heard this one before. A womanizing cad doesn’t believe in true love, even though he makes his living writing novels about it. He sleeps with one beautiful woman after another, never getting attached, always pleased when the women leave before he wakes up in the morning. But his whole world is turned upside-down when, out of nowhere, he actually falls in love with one of them.

Yes, it’s the ol’ “education of a douchebag” story, going by the title “Mercy” this time around and starring Scott Caan, who also wrote the screenplay. (It’s actually his third script; he directed the other two himself, and the first, “Dallas 362,” won the jury prize at CineVegas in 2003.) One is tempted to find autobiographical elements in Caan’s swaggering character, especially since his real-life father, James Caan, plays his dad in the movie, but I don’t know if that’s accurate. But it might be the more charitable interpretation, since without a personal connection there’s no reason to tell a story this generic.

It’s at the release party for his third novel that Johnny Ryan (Scott Caan) meets Mercy (Wendy Glenn), a gorgeous, slender brunette who, unlike most heterosexual women (or so we’re led to understand), is not instantly bowled over by Johnny’s smooth cocky charm. Nor, it turns out, does she like his writing. This wouldn’t normally bother Johnny — he prefers women who can barely read anyway — but in this case it’s troubling because she’s a New York Times book critic. Now with two reasons to pursue her (the usual one, and her negative opinion of his work), Johnny redoubles his efforts to get close to her.

Throughout this, he gives his lovesick friend Erik (John Boyd) the sort of tooly romantic advice you’d expect him to give: avoid commitment, be suave but jerky, etc. At one point, Johnny says, “Usually when women speak I can only hear the teacher’s voice from ‘Peanuts,'” an example not only of Johnny’s shallowness but of Caan’s idea of witty, clever dialogue.

The film is divided, along with Johnny’s life, into two sections: before he met Mercy, and after. The changes in him are obvious to all who know him, including his agent (Dylan McDermott), his married pal (Troy Garity), and his father, a literature professor from whom he is mostly estranged. What’s missing, though, is a point. Love changes a man? Love is fragile and fleeting? Sure, but (not to sound callous) so what? Romantic dramas may not be as plentiful as romantic comedies, but they can be just as formulaic and, without some spark of creativity, just as dull.

Caan was smart not to direct himself this time, handing the reins to first-timer Patrick Hoelck and thus avoiding the appearance of making a vanity project. Were he in the director’s chair himself, his meaty, emotional-rock-bottom scenes would have seemed particularly self-indulgent: “Just look at me ACT!” Instead, they are respectably performed and moderately effective — effective as anything else in the film, anyway. Caan’s past under-the-radar successes aside, “Mercy” never rises above the ordinary, with a bland story and average execution.

C (1 hr., 24 min.; R, a lot of harsh profanity, a fair amount of nudity and strong sexuality.)