The chilling isolation of stardom is the stark take-away from “Gemini,” a smart and knowing film noir set in LaLaland.

Get famous enough, and you’re trapped. Every public appearance is fraught, every social exchange has you questioning motives.

Want somebody you can rely on, trust and confide in? Put them on the payroll. Make them sign an NDA (Non-disclosure Agreement).

Heather, played by Zoe Kravitz (“Big Little Lies”), is the star. Jill (Lola Kirke of “Mozart in the Jungle”) is her trusted assistant.

Jill looks like a celebrity assistant, just pretty enough to have maybe entertained “The Dream” herself, just frumpy enough and self-less enough to be better suited to make somebody else’s dream work out.

Heather is high maintenance. She’s avoiding the famous boyfriend, Devin (Reeve Carney) she just kicked out of their mansion. She doesn’t want to do re-shoots on a movie she finished. She’s ready to back out of one she’s committed to make.

“There’s no MOVIE without you,” Jill protests. Because that’s the deal, poor screenwriter Greg (Nelson Franklin) won’t get financing without her as his star.

And who gets to break that news to Greg at a diner dinner meeting Heather refuses to attend? The same person who gets to screen Devin’s threatening phone calls, the same “assistant” who must deal with the studio that won’t be getting its needed re-shoots, the “assistant” who is more of a manager/father-confessor and BFF for hire — poor, organized Jill.

“You’re the one who remembers things,” Heather purrs, imposing yet another selfish, moderately unreasonable demand on Jill’s time. Jill leaves her tiny Nissan Versa parked while she drives Heather’s Tesla to the discrete karaoke bar, brings Heather from her swank, modernist/Moorish mansion (Spanish tile, floor to ceiling) to her own modest, cute apartment, where Heather makes her least reasonable request of all.

“You’ve got a gun, right?”

Jill, we’ve learned, is a woman of many skills and many layers. She’s smart enough to ask the movie star “You know how to shoot a gun, right?” full well knowing the answer. She’s organized enough to ask the smarter question, “You know how to NOT shoot one, right?”

That, of course, is what happens. The gun is fired. Somebody’s dead. And Jill? She’s a suspect.

Writer-director Aaron Katz (“Land Ho!”) treats Jill’s predicament in screenwriting terms. As in, we’ve heard Devin threaten Heather, and Greg and other film folk and even her agent (Michelle Forbes). There’s a creeper paparazzo. Heather also had a little something on the side, a rich Korean bombshell named Tracy (Greta Lee).

But the detective in charge of the case (John Cho, in his best screen role in years) fixes on Jill.

“You remember things, right?” He picks up on that, too. “You might not think something’s important, and ‘bingo,’ it’s the key to the whole thing.”

Suspect Jill dons a semi-silly disguise and sets about visiting her fellow suspects. Greg is the one who suggests dissecting the clues via Screenwriting 101.

“Motive, opportunity, capacity,” are what “the real killer” requires. Look for the “twists,” as it’s never the most obvious suspect — in the movies, any way.

“You know this is REAL life, right?”

Katz finds a few chuckles via witty, flippant banter (Somebody’s DEAD, remember,), in sharp observations about LA “types” and fairly wallows in production design. The bars, houses are Architectural Digest spectacular, even the “cabins” and tiny apartments.

Kirke, the daughter of Bad Company drummer Simon Kirke, has a Zooey Deschanel deadpan mien, and that lets us totally buy into the “logic” of Jill digging around herself, even if some of her movie-taught sleuthing/getaways are far-fetched.

“Gemini” — yeah, the title’s worth chewing on — isn’t a great thriller. Its Big Reveal is pretty danged obvious, after all. The ending is positively loopy. And it’s a little too sunny and outdoorsy to be top flight noir.

But Katz’s script, settings and characters surprise and delight, and Kirke, Kravitz and Cho deliver performances perfectly in sync with a murder mystery set in Hollywood, as in “Sure, she’s dead, but ‘How’re we wording the PRESS release?’ is the real problem.”

MPAA Rating:R for pervasive language, and a violent image

Cast: Lola Kirke, Zoe Kravitz, John Cho, Greta Lee, Michelle Forbes

Credits:Written and directed by Aaron Katz. A Neon release.

Running time: 1:33