“Landline” tries to pass itself off as a study of families and relationships, all of them in some sort of disarray. It wants us to care about its characters, to take sides with some of them, and to really dislike others. It works, to some degree, on all of the above.

Where it doesn’t work, and what eventually makes it fairly forgettable, is that it also wants us to both sympathize with and at the same time despise one of them, it keeps us wondering too long about whether a couple others are honest or dishonest, and it feels, for most of its short running time, that a big chunk of it has been improvised ... by actors who would be more believable when depending on written words.

It’s set in 1995, which might be why it’s called “Landline,” although there were already cellphones (very expensive ones, mind you) on the market by then. There are some important phone calls made in the film, but that title still confounds me.

It’s really about cheating. We’ve got a recently engaged couple, Dana and Ben (Jenny Slate and Jay Duplass). He’s happy as a clam over them being together. She’s a little less sure. We’ve also got Alan and Pat (John Turturro and Edie Falco), the parents of Dana and her younger sister Ali (Abby Quinn). There are hints that all is not well with mom and dad’s marriage, but it seems to be about going through a phase of not communicating, or maybe being a little bored with each other. But then there’s the “discovery” by the daughters that dad might be writing love letters to a mystery woman. They’re incensed about this, and want to bring it up to mom, but don’t. Instead they bicker with each other over what to do.

Then other hints start rolling in. Dad is a product copywriter who wants to be a playwright. Mom might be involved in politics. Dad is a frustrated artist, and mom is a frustrated person (not enough is revealed about her to go beyond that).

High schooler Ali is fooling around with a boy her own age, and like a realistic teenager, is rude and disrespectful to her parents, regularly cursing at them. What little plot exists starts to cook when Dana bumps into Nate (Finn Wittrock), an old college fling of hers who anyone watching will immediately label a braggart and a cad. He knows she’s engaged, but he asks her out. She knows she’s engaged, so is conflicted, but agrees to a date.

That’s the set-up. Dana is cheating on poor, unsuspecting, good guy Ben, and dad is suspected of cheating — without any real proof — on poor, unhappy mom. Ali is just a little brat. Director and co-writer Gillian Robespierre (“Obvious Child”) wants us to sympathize with confused Dana, but just like her younger sister, Dana acts compulsively, doesn’t think things through.
Unfortunately, she’s also played by Jenny Slate, an actress who needs a director to tell to reel it in a bit. It’s very hard to feel sympathy for a character who’s behaving badly and is being played in an annoying, almost grating manner.

To be fair, there is some thoughtful (obviously written) dialogue mixed in with some that’s just silly. But that doesn’t add up to enough when the film keeps jumping forward to new episodes of its story, leaving the feeling that some of the scenes haven’t been completed. A couple of them, involving a heroin deal, only clog the film’s minimal flow, and should have been left on the cutting room floor.

So, can there be resolution? Does confession solve a problem or make it worse? Do blatant confrontations result in anything positive? Those questions are answered here. But like the actions of the sisters, they don’t feel like enough thought was given to them in the script. Or maybe they just weren’t improvised very well.

— Ed Symkus writes about movies for More Content Now. He can be reached at esymkus@rcn.com.

“Landline”
Written by Elisabeth Holm and Gillian Robespierre; directed by Gillian Robespierre
With Jenny Slate, Abby Quinn, Jay Duplass, John Turturro, Edie Falco, Finn Wittrock
Rated R