An attractive young cast filled with Broadway up-and-comers isn’t enough to spark the neo-noir murder mystery “Seaside” to life.

A drab, mostly-sterile affair, it takes on a “Pretty people in a pretty setting in search of suspense” vibe and never really shakes it.

But like a lot of movies in this low-budget price range, there’s enough here to justify making it, even if the execution is off.

Police tape on an Oregon beach opens the film, so we know somebody’s going to get it. But who, and who will do it?

Ariana DeBose, a girlish, winsome presence cast in Spielberg’s upcoming “West Side Story,” stars as Daphne, a 24 year-old in a dead-end job trying to care for her broke and out of work mother (Sharon Washington).

They’re one Wells Fargo mortgage notice away from losing their house.

But Daphne has a secret she’s keeping from Momma. Daphne sneaks out and sees an old flame, Roger (Matt Shingledecker). Roger’s helping care for an aged father.

And then Dad dies. No more sneaking into Roger’s room after hours.

“You can go out the front door now…We’re free.”

For a guy who’s just lost a parent, Roger is downright giddy. He sasses his late father’s lawyer (Jana Lee Hamblin) when he drags Daphne in for the reading of the will. Law lady may have been the old man’s lover, at one time. She’s there to pop the kid’s bubble.

“Bar-tending while you’re waiting for your inheritance is not a career.”

Roger gets the beach house in tony Seaside, and nothing else. His heirs — should he marry and father a child — get it all.

So that’s what Daphne meant when she corrected her beau’s misuse of African American slang.

“Just stick to your rich stoner white boy talk.”

He’s rich. He’s “Let’s get married!” impulsive. And Daphne? We don’t see her using the toilet for nothing. She gives that birth control dispenser a good, hard look on the counter.

A trip to that beach house, a testy encounter with one of Roger’s exes (Steffanie Leigh) and all we have to guess is who is going to wind up a corpse behind that beachside police tape, and who or what put them there.

The muted color palette and minimalist, downbeat score contribute to the monotony of this potentially-intriguing thriller.

Because those production elements match the underplayed performances. A drunken shout here, a glower there, that’s all “Seaside” writer-director Sam Zalutsky gives us for fireworks.

Everything, from sex scenes to phone arguments to a police investigation, floats along on the same enervated plane. Scheming? Sure. But watch “The Postman Always Rings Twice” — either version. There’s got to be some heat somewhere, some rage, paranoid panic.

The tempo of unfolding events needs to quicken to pull the viewer in, but we’re treated to so much wasted time — shots of walking, driving, thinking — that slow the pace to a crawl.

The wedding scene, in which the happy couple buy the proper gown and tux and then show up in a church, with no appointment and no paperwork, is laughable but has the spark of tetchy life to it.

“We’re ready for business…

“Can I see your license?”

“We’re in love. Isn’t that enough?”

Who, even in his or her early 20s, doesn’t KNOW that you need a license?

When Roger says, the wind leaving his sails, that maybe that was “a sign,” we get it. It’s a sign you’re a rich dope. And if Daphne’s supposed to be the cunning one, you’ve got to wonder about her, too.

This plot, with its murderous, sexy love and murder entanglements, can work. This cast might make it come off, when more of them have movie and not mostly stage experience.

But it doesn’t and they don’t and if we wonder who DIDN’T do it, all signs in this mystery point to the script and the fellow who wrote its direction of it.

MPAA Rating: unrated, violence, sex, nudity

Cast: Ariana DeBose, Matt Shingledecker, Steffanie Leigh, Sharon Washington, Jana Lee Hamblin

Credits: Written and directed by Sam Zalutsky.  A Gravitas Ventures release.

Running time: 1:33