“Starlet”: Have you heard the one about the octogenarian and the porn star?

It sounds like the worst sitcom on Lifetime: a beautiful young porn actress befriends a cranky old lady with a bingo addiction.

And yet Sean Baker’s “Starlet” works hard to avoid any sort of cliche, or any audience expectations at all, really. Instead, it’s an unsentimental yet moving indie drama that keeps allowing its two main characters to reveal deeper and deeper layers beneath their easily stereotyped facades. It’s exactly the sort of well-crafted low-budget indie that Madison needs to see more of in theaters, so audiences shouldn’t miss the chance. “Starlet” screens for free in the Union South Marquee Theater, 1308 W. Dayton St., at 7 p.m. Thursday and Saturday.

Dree Hemingway (daughter of Mariel and great-granddaughter of Ernest) makes an assured lead performance as Jane, a languid 22-year-old Florida transplant who bides her time in California’s San Fernando Valley, a sun-dried wasteland of cheap apartments and strip malls. Dree and her two deadbeat roommates (Stella Maeve and James Ransone) dabble in porn to pay the rent. Dree seems smarter than her roommates, less desperate and deluded about her circumstances, but one of the fascinating aspects of “Starlet” is discovering how much of her worldliness is real and how much is just a pose. Hemingway’s nuanced (and often funny) performance keeps us wondering.

Jane’s moral compass is put to the test when, at a yard sale, she buys a thermos for a dollar, takes it home and finds that it’s filled with tightly-wrapped wads of cash. She immediately goes on a shopping spree, but then, out of a sense of guilt or just curiosity, starts visiting the 85-year-old Sadie (Besedka Johnson) she bought the thermos from. Sadie is hilariously crotchety and resistant, but Jane is so doggedly, cheerfully persistent that Sadie finally starts to warm up to her.

Their friendship goes nowhere you might expect — Sadie doesn’t teach Jane any hard-won life lessons, and Jane doesn’t try to rekindle Sadie’s lost youth. There are no montages here. Instead, Baker shows how their completely different worlds slowly find an intersection point, tentatively. I love how Johnson (in her first acting role) never makes Sadie the least bit likable; she’s a genuinely prickly and difficult woman to the end, and yet makes us feel for her deeply.

Baker opts for a very naturalistic style in the vein of Kelly Reichardt (“Old Joy”) or Kenneth Lonergan (“You Can Count on Me”), allowing scenes some space for awkward pauses and meaningful glances, for the hesitations and awkwardness of real interactions. He has one favorite technique he employs several times, letting the twinkling music on the soundtrack build and build, and then suddenly shutting it off cold.

The film features some explicit sex in its portrayal of the adult film industry, but what’s more shocking than the nudity is how incredibly boring porn looks for all involved. Baker lets the film spend a little too much time in this world, especially following the hapless exploits of Dree’s roommates, who, incredibly, seem too dumb even for porn. I kept wanting to get back to Jane and Sadie, how Jane grins wickedly as she prods and pokes Sadie into some kind of response, and how Sadie, after a withering flicker of her eyes, finally allows herself to light up a little.