This past year may be remembered as the one mumblecore — the semi-disputed subgenre of American indie film wherein awkward young hipsters stumble, fumble and mumble their way through love’s fragile foibles — grew up. Or at least graduated from the festival circuit to the multiplex, with Noah Baumbach’s Greenberg and Mark DuplassCyrus channeling mumblecore style and spirit with, for the first time, bankable Hollywood stars. Cyrus, an uncomfortable black comedy about a blossoming romance stymied by the female lead’s disturbed son, was shot for just $50,000 and grossed more than $7 million. It’s not Nirvana outselling Michael Jackson in 1991, but it proves mumblecore isn’t a fly-by-night trend.

It’s likely that through Mark Duplass’ successes — he also directed the well-received Puffy Chair and Baghead, which played in limited release — his wife, actress Katie Aselton, was able to complete The Freebie, her first mumblecore feature as writer-director. With Duplass signed on as executive producer, Aselton shot the 78-minute feature in 11 days, working collaboratively with the cast from a six-page outline. The result, which opens Friday, Dec. 31 exclusively at the Coral Gables Art Cinema, doesn’t expand mumblecore’s lo-fi vocabulary, but it tells a damn fine story within the genre’s conventions.

It’s an idea that might have originated from the late French auteur Eric Rohmer in his prime. A young couple, monogamous for some time and still gooey-eyed for one another’s company, has seen their sex life dwindle to a state of seemingly comfortable obsolescence. Neither Annie (Aselton) nor Darren (Dax Shepard) can remember the last time they made love, the status of their loins reduced to sarcastic punch lines. Affection and mild discomfort commingle in an early scene where Annie dons a bikini to spice things up, a move received with awkward compliance by Darren until the couple gives up, resigning themselves to a night of crossword puzzles before bedtime.

To help them get past this hurdle, Darren proposes that each of them be granted a free evening on the town to have a one-night stand with a stranger, thereby getting the pent-up sexual frustration out of their systems and allowing them to start anew. It fits the stereotype of the seed-planting male that Darren, rather than Annie, suggests authorized philandering as a way to save monogamy, an idea that sounds patently absurd and seemingly destined to be shot down by his significant other. But Annie goes along with it, and both parties begin to prowl for a mate, with one landing an intimate, indie-folk-scored bedroom encounter and the other a dirty barroom fuck.

Or so it seems. The genius of Aselton’s narrative — spoilers may be contained herein — is that she doesn’t show the actual fornication. The results of the intended trysts are left to our own expectations and perceptions of the characters. We’re asked to take them at their words during a climactic argument, but neither sounds very convincing. The truth is smartly, deliberately murky, providing one of many angles for this interactive movie’s attendees to discuss during what should be a lively ride home from the cinema. Other themes addressed include the sustainability of a healthy but sexless relationship, the impossibility of sex without emotional involvement and a questioning of monogamy as the standard, de facto lifestyle choice for mainstream society.

Hollywood would never breach these subjects with such nuance or maturity, nor would conventional, populist moviemakers cast two lead players who look this refreshingly ordinary. By stripping the film of cinematic artifice and observing these characters — warts and all — Aselton seems to be suggesting that this easily could be you. Whether it’s seen as a cautionary tale or wish fulfillment is in the eyes of the beholder.