In the trailer for “In the Land of Women,” it’s hard to tell much about what’s going on, other than that Adam Brody whines and rambles and flashes his token sheepish grin to a sympathetic-looking Meg Ryan. And really, that’s all you need for a successful romantic comedy ­— sure, he may essentially be acting like Seth Cohen but, as he proved in his brief-but-hilarious cameo in last year’s “Thank you for Smoking,” recycling some of the charm he was know for on “The O.C.” may not be such a terrible thing.

“Land” is the directorial debut of Jonathan Kasdan (son of director and screenwriter Lawrence), and the young director has apparently decided that, while he can make use of Brody’s considerable charisma, the character must be forced to act more grown-up. Unfortunately, the movie doesn’t really follow suit, and the script (also by Kasdan) ultimately offers a frustratingly vague and shallow look at relationships. It also pales in the inevitable comparison to the elder Kasdan, who wrote “The Big Chill” — the ultimate movie about relationships and being forced, feet dragging, to enter the adult world once and for all.

“Land” opens with Carter Webb (Brody), an aimless 26-year-old who is currently employed as a soft-core porn screenwriter, being reduced to a teary-eyed emotional wreck by his soon-to-be ex-girlfriend Sofia (Elena Anaya). She needs some space, and so Carter decides to decamp to Michigan to regroup and finally write a novel about growing up in Los Angeles.

And so to Michigan he goes, arriving at his grandmother’s ramshackle house on a leafy suburban street that looks like it’s been drenched in a Technicolor autumn palette of purples, oranges and greens. Despite the increasing eccentricity of his grandmother (Olympia Dukakis, who steals every scene she’s in), every room in her modestly sized house is imbued with a golden warmth. This makes the home across the street, an enormous crypt-like house with cold metal countertops in the kitchen and chilly blue paint on the walls, seem even more frozen in comparison. It doesn’t take much to guess that the family who inhabits it has issues with intimacy, and it doesn’t take a genius to figure out that Carter’s going to help those Hardwicke women figure it all out.

For the most part, you can see early on where “In the Land of Women” is headed, and it doesn’t go much of anywhere. The Hardwicke women (played by Ryan and Kristen Stewart) endure emotional anguish and, of course, must learn some lessons along the way. Carter, after sufficiently complicating everyone’s life, begins to stumble towards whatever he’ll end up doing in life (chances are, write about this trip to Michigan) and heads home. But as the credits roll, it’s hard to say what the point of it all was.

Maybe that’s because Carter, who should be the movie’s center, is something of a blank. After all, he’s the man plunked down in this “land of women,” each of whom is compelled to bare her soul to him. But we never see what it is about him that’s so magnetic, other than that he’s kinda hot. After all, he’s not even Adam Brody (aka Seth Cohen) at his best, and there’s an early joke which implies that he’s self-centered and a bad listener. So what is it about Carter Webb? And if there’s no answer to that question beyond, “Women love Adam Brody,” then what is it about this movie that should keep viewers in their seats?