A marriage unravels over a summer of discontent set at a Catskills country house in Hilary Brougher’s slice-of-life drama. It kicks off when a man hides in a bedroom to conceal a major secret from his wife, starting the film at a high, tense pitch that makes the rest of the film feel deflated afterward. Yet with the pensive longueurs and necessary compromises that come afterward, the episodic story redeems itself as a character study and a statement on a certain kind of bohemian, middle-aged state of mind.

Lila (Talia Balsam) is sexy in an earth motherly way, and bound tightly to family life. At her house deep in the countryside, she manages two daughters, each a handful; nurtures a friend (and fellow mother) who is facing cancer; and watches her hunky but evasive husband, Edgar (Scott Cohen), with a justifiably wary eye. Hip on paper but weak at the bone, this man is making a fool of her and rashly destroying their family. His betrayal will be a catalyst for a series of big and small events that the filmmaker presents with a resigned, deadpan skepticism very much reflecting the attitude of the film’s heroine.

In recounting the collapse of its central relationship, South Mountain layers human behavior with dramatic acts that may make some viewers raise their eyebrows. Confronted with Edgar’s creepy infidelity, Lila takes a bold step, aiming for revenge. It doesn’t seem wholly believable, and neither does Edgar’s willingness to forget it so soon. However, other domestic interactions ring very true: the awkward silences that arise when parents negotiate a peace between two sulky sisters, a mother’s unspoken worry about a headstrong teenager.

The landscape echoes the film’s mood shifts: the breezy, endless summer afternoons and when mountains and ominous skies loom over the action. Moments of unexpected affection, tension, and connection draw you into the story, and Balsam’s natural, relatable performance anchors its ebb and flow. At the end, we’re left with an uneasy truce. Not the most satisfactory ending, to be sure, but probably the most realistic one.