We meet the three couples as they sit in a circle around a fire pit outside a Michigan cabin on a sun-dappled afternoon.

As the camera orbits the half-dozen friends, who appear to be in their early 30s, a woman named Peggy reads aloud from the horoscope section of a newspaper and mentions “Mercury in Retrograde,” i.e., the illusion the planet Mercury is moving backward from our point of view on Earth.

Over the course of the long weekend, we come to see whether the astrological prognostications are accurate — and how by Sunday, just as Mercury Retrograde isn’t what it appears to be, perhaps not all of the romantic relationships (and friendships) are what they appeared to be on Friday.

Writer-director-producer Michael Glover Smith’s “Mercury in Retrograde” is a smart, funny, quietly effective and authentic slice of older millennial life, focusing on three Chicago couples who drive up to Saugatuck, Michigan, for a three-day mini-vacation.

Our pairings:

• The amiable Jack (Jack C. Newell) and the lovely, spiritual Golda (Alana Arenas), who have been married for a decade. Jack is the host for the weekend. (It’s actually his father’s cabin.) They don’t have children. Might they want children? Is there an issue?

• The beautiful and blunt, French-born Isabelle (Roxane Mesquida) and the self-centered, slightly jerky Richard (Kevin Wehby), who have been together for five years but are not engaged and do not live together, due to Richard’s commitment and maturity issues.

• The handsome and laid-back Wyatt (Shane Simmons) and the aforementioned Peggy (Najarra Townsend), who is sweet but seems a little anxious — perhaps because she’s new to the circle, having dated Wyatt for just a couple of months.

Writer-director Smith has a deft touch for dialogue, creating six distinct characters who look and sound like people we know — or in some cases, people who might cause us to roll our eyes just a little bit when they delve too deep into self-involved hipsterism. (Let’s put it this way: Richard is seriously into Frisbee golf, and he says the only reason he agreed to the trip is there’s a nearby course that was given a grade of A- on some Frisbee golf website. Settle down, Richard.)

The secluded woodlands setting is idyllic and is just the right spot for bonding and trysting and brutally honest confrontations, though in a different genre it would be the kind of place where one goes off for a walk and never returns. (Peggy takes note of this on the first night, telling her amused boyfriend Wyatt there’s no way she’s getting any sleep.)

Smith’s camera hovers around the characters and sometimes pulls back for deliberately casual medium shots that give “Mercury in Retrograde” an almost documentary feel. One can’t say for sure if ad-libbing was encouraged, but the interaction between the uniformly excellent actors feels natural and unforced.

And really, it’s all about the dialogue, and the revelations, and the confrontations. At times it’s as if we’re watching a filmed play — especially when things take a dark turn in the final act, and one character reveals some shocking truths.

But even that “big” scene contains a smaller truth about how we sometimes find it easier to tell our deepest secrets to a near-stranger than to those closest to us.

We also get some absolutely beautiful if heartbreaking moments, as when Isabelle translates a French poem to the ladies, explaining how a woman is sitting with a man in a cafe, and he is having his coffee and not talking to her, smoking a cigarette and not talking to her. It’s too bad Richard isn’t there to hear what Isabelle is saying.

“Mercury in Retrograde” ends with Peggy updating us on her life and the lives of the other five characters. I’ll not give anything away other than to say just about everything that eventually happens to them was set in motion on that weekend in Michigan.

★★★

Retrograde Films presents a film written and directed by Michael Glover Smith. No MPAA rating. Running time: 105 minutes. Screens at 8:15 p.m. Friday (sold out) and 7:45 p.m. Monday and Wednesday at the Gene Siskel Film Center. Smith and actor-producer Shane Simmons will be present for Q&A sessions after each screening.