Finn Wittrock of “The Big Short,” “La La Land” and TV’s “American Horror Story,” makes a reasonably charming rogue with his hooks in the girl who got away in “Write When You Get Work,” an amusing-enough “long con”  comedy set among Long Island lowlifes transplanted to the Big City.

Pair him up with with Rachel Keller of TV’s “Fargo” and “Legion,” and make veteran character Brit Emily Mortimer (“Match Point,” “Shutter Island”) as the crook’s “mark” and you’ve got a caper picture that hides its cards and toys with our affections and gets away with it — more or less.

The opening credits show Ruth and Jonny as young lovers — sex on the beach, genuine passion, pregnancy test, Jonny slamming the door in Ruth’s face when she’s delivering the news.

Long Island, right?

“Nine years later” and Jonny’s still not wholly an adult. The petty theft and breaking and entering continues because his ability to hold a “straight” job is still a rite of passage he’s not mastered. Then a major figure in his life dies — his high school coach. Coach was important to Ruth, too. It’s just that they avoid each other at the funeral.

Ruth has straightened out her life, moved beyond Jonny. She’s interim admissions director at a posh girl’s school — Luscinia .

Jonny’s the last thing she needs in her life, as the school’s rich board of trustees and snobby school administrator (Jessica Hecht) already look down their noses at her. Jonny breaks into her flat.

“Could you leave me alone?”

“Those windows are an open invitation!”

And with every intrusive, probing question (he does this to EVERYbody), Jonny grows more determined to inject himself into her life and her work.

Ruth is alarmed. Of course he’s there looking for prey. That’s what predators do. He sees the parents of her students as pigeons and he keeps showing up at work, taking tours and ingratiating himself with the most vulnerable parent-pigeon at Luscinia — Nan (Mortimer).

Her husband’s a hedge fund hustler in trouble with the Feds. And she is in a panic, wanting to hide assets. Prospective Luscinia parent Jonny might be just the guy to help her “hide” cash and jewels, should the worst come to pass.

Ruth’s suspicions about Jonny may be why she lets him charm/bully his way back into her life. Keep him close enough to figure out his angle. Or maybe she’s still smitten with him, after all the hurt, after all those years.

Of course it’s more complicated than that. Otherwise, she’d call the cops or stalk him and shoot him, right? A clue might be his joke on hearing what her job title is.

“Director of admissions, huh? What are you trying to make them admit?”

Jonny’s got his “boys,” the old gang is still together — a bodega clerk here, a side-hustle waiter or doorman there. Writer-director Stacy Cochran (the Winona Ryder ’90s vehicle “Boys” was a high water mark, as was the ’90s Diane Lane film “My New Gun”) never has an overt “assemble the gang” scene. “Write When You Get Work” is more subtle than that.

The Ruth/Jonny relationship has a simple “You’re still immature” vs. “You forgot who you are” conflict. He’s never outgrown pilfering, she’s “living (her) life with strangers.”

Mortimer makes Nan every entitled Monied Classes apologist, with her “You have no idea what the government DOES to people like us!” Can’t have “the mark” too sympathetic.

Wittrock plays the lighter side of vile, pushing us to root for Ruth even as we wonder about her secrets and wish she’d put up more of a fight. Jonny gets a job as a coat check guy in a club, and right off he’s stealing people’s coats. He’s a crook for life.

And Keller gives Ruth a just-beneath-the-surface street edge that suggests she’s not utterly in the dark about Jonny’s new con. She’s figuring it out, as are we. Her secrets make her subject to blackmail from all sides. How WILL she extract herself from Jonny’s snare?

The dialogue has a light sparkle to it, even as some of the situations seem needlessly contrived. But Cochran has conjured up a caper that’s just clever enough and characters just winning enough to hold our interest long enough to be surprised at the resolution to the puzzle that she conjures up.

Cochran’s gone years and years between feature film projects. “Write When You Get Work” makes one glad she wrote — and got work.

MPAA Rating: unrated

Cast: Finn Wittrock, Rachel Keller, Emily Mortimer

Credits:Written and directed by Stacy Cochran. An Abramorama release.

Running time: 1:39