From its opening scene, moral responsibility is at the center of “A Separation,” an Iranian film that chronicles the fallout of a husband and wife and the residual damage that accumulates thereafter. Simin (Leila Hatami) sits before a judge, requesting a divorce from her husband Nader (Peyman Moadi) on the grounds that he refuses to accompany her and their daughter to Europe, where Simin believes a better life awaits them.

Nader, whose elderly father is stricken with Alzheimer’s, feels his hands are tied. Ultimately, the judge deems a divorce unnecessary and rejects Simin’s application, keeping their marriage intact. Such a process will seem alien to Western audiences, but as the film trudges on, Iran’s arcane legal processes proves the perfect backdrop to the increasingly complex and murky narrative that unfolds.

After deciding to separate, Nader hires Razieh (Sareh Bayat) to help care for his father. From a decidedly lower class of living, Razieh is forced to make an hour-long commute with her 5-year-old daughter in tow. One day, Nader returns home to find things in disarray (Razieh is at first nowhere to be found and his father has been tied to his bedpost, unable to move), resulting in an explosive argument that leads to Nader forcing Razieh out of his home.

In the tussle, Razieh slips and falls down a flight of stairs. She winds up in the hospital after miscarrying. Nader claims the fall was not his fault; he also claims he had no idea she was pregnant. Razieh’s husband, Hodjat (Shahab Hosseini), disagrees vehemently, calling Nader a liar who hired Razieh without first asking his permission as required by Iranian law.

From there, the story only becomes more intricate. Remarkably—miraculously, even—writer-director Asghar Farhadi keeps it all in check with a style that’s as hands off as it is calculated. “A Separation” boasts a stern naturalism fitted with characters and emotions that feel entirely tangible. The stakes presented by the narrative are sky-high, and Farhadi’s camera, which is probing without being intrusive, acts as an observant spectator.

Because the film revolves around a series of conversations, Farhadi also relies on clever formal techniques to heighten the tension. He edited “A Separation” like an action film, using hard cuts and graphic matches to keep a sort of edgy continuity from scene to scene. The film’s deliberate plotting is perfectly suited to exacerbate the mounting tension.

What results is a perfect storm of montage to accompany a richly layered narrative that is devoid of heroes and villains, but instead is comprised of people with the capacity to be both. True to real life, “A Separation” features inherently decent characters whose desire to do good is threatened at every turn, either internally—in the humanist sense—or externally, represented by Iran’s convoluted judicial structure.

Each of the four principals appears bound by these external forces, with Farhadi paying special attention to religious beliefs, financial concerns, societal obligations and general classism. But where a more scornful director might pass judgment against those who abide by such rules, Farhadi is ultimately sympathetic, maybe even slightly apathetic.

In fact, he reserves his most obvious judgment for the very last scene, one that involves a fateful decision from Nader and Simin’s 12-year-old daughter, Termeh (who is played by Farhadi’s actual daughter, Sarina). Her voice refused at every turn, in this final moment Termeh is given a choice of her own, and the final, lingering shot is one likely to be burned in the annals of cinematic images for years to come.