Hilary Swank’s screen career is a stark reminder that all an Oscar or two really gets you is the attention of filmmakers with a challenging role to offer, and perhaps just enough money to get that film made. Because a star who is “not box office” is the label that matters to most everybody else in the movie business.

“The Good Mother” is a case in a point, a timely but somewhat perfunctory mystery/character study from director and co-writer Miles Joris-Peyrafitte, who once made “As You Are.” There are good things about it, but nothing great and nothing all that worthy of our attention. But the cast battles any low expectations it might create and gives the viewer something to hang onto.

The first time Marissa (Swank) and Paige (Olivia Cooke of “Thoroughbreds,” “Pixie,” “Me and Earl and the Dying Girl”) see each other on screen here, Marissa gives the younger woman a slap so hard she knocks her down.

They’re at a funeral. Paige is plainly pregnant. And yet Marissa needs someone to blame for the drug-related death of her son.

“You know, I didn’t make him a junky,” the mother-to-be tells the distraught, grieving mother of Mike. “The Good Mother,” a “problem drinker” who has let life beat her into alcoholism, is a far better candidate for that, if the movie is inviting us to fix blame.

Marissa is an Albany newspaper editor, once a gifted writer “who won’t write,” her boss complains. Her other son, Toby (Jack Reynor) is a cop. It’s pretty obvious that no one in her life can count on her, and that went for the dead son as well. She’s always knocking them back at her lonely neighborhood bar, finishing off another bottle at home, passing out, sleeping through appointments, and when she goes back to work, maybe even sneaking a nip or two in her coffee.

But whatever or whoever killed Mike had something to do with this hot new drug, “Mother’s Milk,” “heroin coated fentanyl.” Paige finds his stash and flees the goons who bust into her place to get it.

Marissa is resigned to taking her in. Paige, having a roof over her head and no visible means of support, decides she’s going to do what officer Toby can’t. She’s going to find Mike’s killer.

Everything in that last paragraph is what I mean by “perfunctory.” Plucky, pregnant Paige doesn’t let pregnancy or danger or no experience in investigating dissuade her from this impulsive pursuit. The tippling reporter-on-leave she’s living with should be the curious one, the furious one wanting justice. But she has to be shamed back into that.

Joris-Peyrafitte allows room for detours into a grief group meeting (but not AA) and a pregnancy sidebar that sees Toby and his wife Gina (played by the Dominican actress Dilone of “The Novice) trying to have a baby, letting Gina and recovering-junky Paige bond.

But all those distractions and “The Good Mother’s” brief running time can’t keep us from too-quickly solving the mystery, after failing to make us invest in that solution.

Swank plays this part so internally that there’s not much to latch onto. And Cooke never has the screen time to give Paige the layers of damage a pregnant addict should have. Where’s the Mother to Mother mistrust?

The third act’s unraveling of the plot is pretty interesting and well-handled via close-ups that at least show us who and how, if never why.

“The Good Mother” doesn’t just feel perfunctory in the ways it skips straight into under-motivated behavior and actions. It feels incomplete. “Whodunit” is less of a mystery than “why” they done it, or why everybody else behaves the way they do in what could have been a more compelling, engrossing film.

Rating: R for language throughout, some violent content and drug material.

Cast: Hillary Swank, Olivia Cooke, Hopper Penn, Dilone and Jack Reynor

Credits: Directed by Miles Joris-Peyrafitte, scripted by Madison Harrison and Miles Joris-Peyrafitte. A Vertical release.

Running time: 1:30