**Mild spoilers included, so don’t read if you haven’t watched the show**

Love is messy, and marriage then takes that material and tries to write a novel with it. Sometimes it’s sad and other times beautiful, but the weary pushback of life and your own DNA can eventually drown a union that at once seemed free and immortal. But the dead truth is that love is very mortal, and needs all the care and respect that a single soul can fathom.

Most of the time, the movies and television fumble this concept. It’s either overly artificial or ruefully dramatic, held hostage by human steam pipes who never had a real best friend to vent to. But every once in a while, someone nails it. The script and dialogue are dead-on about how two strangers fall in love and try to make it last. The latest case of the arrow hitting the center of the cinematic (the best television shows feel cinematic) bullseye is Hagai Levi’s HBO series, “Scenes from a Marriage,” which concluded its run Sunday night.

Starring Oscar Isaac and Jessica Chastain as the married couple on the verge of, experiencing, and dealing with the aftermath of separation and reconciliation. If that last part sounded like a hammer slowly jabbing your brain repeatedly, then mission accomplished. That’s what the Israeli writer/director and showrunner serves up for viewers here: a fascinating, if brutally honest and intense, portrayal of love, marriage, betrayal, separation and rectification. Isaac and Chastain are absolutely phenomenal in complex yet highly personal roles; long-form dialogue readings that every actor dreams of having once in a project happens frequently here. Each of them tears into the parts of Jonathan and Mira, respectively, with a blend of ferocity and tenderness that just hits different.

But the extra layer of intrigue here, beyond the brilliant combination of great actors and searing writing, is the breaking of the fourth wall. At the beginning of most episodes (there are five total), audiences see what looks like a behind-the-scenes peek at the actors prepping or walking to the set to film a scene. And once “action” is said, the entire screen transforms from a set with 50 people on it to an intimate gathering or 2-4. It’s not gimmicky or overdone, but it portrays a sad-but-true dichotomy often found in real-life marriages. Is marriage real, or is it a fairy tale we hold together in our heads with duct tape?

With “Scenes from a Marriage,” Levi is challenging the theory of happily-ever-after, portraying it more like two people madly in love with each other yet playing a part that life has chosen for them at the same time. We see Isaac’s Jonathan and Chastain’s Mira in love and together, with a young daughter, during the first episode — which largely takes place at a dinner with friends (Nicole Beharie and Corey Stoll). They are sweet yet slightly combative, especially after an argument brings the night to a screeching halt. Jonathan defends his friend while Mira goes the other way — the form of useless couples fighting that nobody takes on the scorecards yet sees their oxygen tank drained.

Throughout Levi’s show, that’s the meatier portion: two people who fell in love and don’t understand how they fell out of love. An endless rendition that will scare away some viewers should also pull many others in with its relentless, honest approach. Seeing the walls down at first — the crew throwing last-second makeup on the actor while taking their phone and drink before the director calls action — is ingenious because it portrays love not as a fantasy but as a moving and breathing play. It’s not Isaac and Chastain going back to their rooms/trailers — it’s Jonathan and Mira, walking in robes through a warehouse-turned-gigantic set, the two we just watched wrapped in each other’s arms in bed at an Airbnb.

Why not play with the idea of people making shows about people in love? Levi isn’t afraid of that dichotomy; he runs towards it with open arms here. If you came into this show knowing nothing, I think the point of view chosen is wildly successful. Is that how it came together in Ingmar Bergman’s head back in the 1973 mini-series and 1974 movie of the same name? Forget the answer, and appreciate Levi’s engrossing take.

The episodes fly by with an unpredictable pace, the wicked kind that writers can use to explore all sorts of uncomfortable truths that most people want zero part of. It’s like being a fly on the wall during the collapse and semi-rebuild of a union — the who, what and why of it all, and how other events can throw it for a loop. There’s a scene where Mira is in a hospital room with Jonathan following a procedure, and you can just feel the tension: the slow untying of a knot. Another sequence, centered around Jonathan and Mira returning to the house under unusual conditions, experiences an evening that both reaffirms and shatters whatever stood firm years ago.

If I had to compare the writing and acting to anything, it would be “Closer,” Mike Nichols’ 2004 acting masterclass starring Julia Roberts, Clive Owen, Jude Law, and Natalie Portman. You don’t hear two people in love talk this way often in movies or TV shows. It’s not like those other showrunners and creators purposefully missed the destination; they just couldn’t find it. Levi, along with Amy Herzog (she co-wrote the teleplay in two episodes), found the destination.

Raw yet honest, “Scenes from a Marriage” examines the good, bad and ugly of love and partnership: one of life’s messiest, yet highly unbreakable, emotions. If you just need one reason to watch, do it for the acting. Isaac and Chastain have never been better — and that’s saying a lot.