‘Somebody I Used to Know’ feels only half cooked

“Somebody I Used to Know” makes a good effort at putting a new twist on a standard romantic-comedy trope.

But it never quite gets there.

The film is directed by Dave Franco, who wrote it with Alison Brie, his wife and the film’s star. “The Rental,” Franco’s feature debut as a director, was a nice spin on stalker horror (which also starred Brie).

The latest film doesn’t quite measure up. Brie plays Ally, the host of “Dessert Island,” a reality show that is a kind of combination of “Sugar Rush” and “Love Island.” The film gets this just right – the absurdity of the fauxemotional testimonials, the vapidity of the contestants.

We catch up with Ally as she is taping the season finale which, she learns to her shock, is also the series finale. The show is being canceled. With no particular plan, she leaves LA on a whim for her childhood home of Leavenworth, Washington. An awkward reunion with her mother (and a former teacher) leads her to a local bar.

There she runs into Sean (Jay Ellis), her former boyfriend who she left for LA, wanting to make documentaries before finding success with … “Dessert Island.” It’s hard to tell whether Sean thinks Ally is a sellout or just upset she left him high and dry in their hometown. Either way, the breakup clearly was not amicable.

But everything seems happy now. A bunch of drinks and soft pretzels lead to a rom-com montage of an afternoon and evening in which it becomes clear there is still a spark between the two. Just when things are about to get really serious, though, Sean cuts out.

With good reason. The next day we learn that Sean is engaged to Cassidy (Kiersey Clemons).

OK then. Perhaps you have seen this kind of movie before. Franco and Brie know that you have, in fact, namechecking “My Best Friend’s Wedding” – though to say that this is not like “My Best Friend’s Wedding.”

Maybe not, but no matter how hard you try to break the rom-com rules, certain of them must be observed. For instance, Ally shows up in town just a couple of days before the wedding. Of course.

There is a version of this kind of story where Cassidy is a shrew and the audience knows Sean would be better off without her. To Ally’s dismay, Cassidy is loving and nice and really cool. Which does not stop Ally from doing some pretty awful things in an attempt to steer Sean her way.

What’s new here, in fact, is just how selfish Ally is. There are times when she and Cassidy bond, seemingly, but for much of the film it’s just a means to an end for Ally.

Her old friend Benny (Danny Pudi, quite good in a small but important role) warns her that things are going too far. Ally knows it, but can’t seem to help herself. Brie is always a welcome presence – see “GLOW” if you haven’t – but the film depends mightily on her charm, which, while plentiful, sometimes isn’t enough.

And there is little margin for error. You don’t have to actively root for Ally to succeed in her scheme. But you shouldn’t root so strongly against her – not just her plan, but her entire persona. She’s got an ugly side that consumes most of the other sides for a large chunk of the movie.

Brie is a gifted comedic actress, with a confidence that’s admirable. Ellis makes Sean likable, if confused. Haley Joel Osment is funny as Sean’s brother, a good-time goofball.

But “Somebody I Used to Know” never fully finds its footing as a romantic comedy. It plays more like an unfinished script, one in which the kinks haven’t been worked out yet. Another couple of passes at the whole thing and Franco and Brie really might have had something.