One of the few must-see films in theaters this summer was Matt Ross’ Captain Fantastic. A drama about an off-the-grid, beyond-hippie dad whose abilities as a parent are challenged by his wife’s absence to battle an illness, the story eventually becomes As I Lay Dying in reverse- and I’ll leave it at that.

Ross wrote a very original script, and Viggo Mortenson is getting praise for his performance as the dad, and rightfully so, but the kids are moving too. Still, any time an indy film like Captain Fantastic strikes a nerve – and it ballooned in July from four screens to over five hundred, before deflating again this month – I wonder why. Why this film? Why now?

Thrift Store Olympians Unite! Viggo Mortensen and (half) his brood in “Captain Fantastic.”

Well, the psychological journey in Captain Fantastic is remarkably similar to the Bernie Sanders moment in American politics. For millions of idealists it was the month the bill came due, the season of acceptance and resignation.

In any case, the arc of the hero’s journey here is remarkably inward-looking. It’s the dad’s struggle to keep fighting or to relent in the face of his father-in-law’s overwhelming case for why the kids should leave their revolutionary upbringing behind. It’s a beautiful, elegant script, to have so much action, but the heart of the drama spinning around the axis of a person’s decision whether to keep on fighting.

If anything, I’d say Ross the writer plays too many cards to prove his point. The scene in which eldest son Bo mangles his first romantic tryst with a girl at a campground by breaking down and proposing marriage to her drives the point home far enough – that these kids are truly not prepared for life within cell phone range – we don’t need the wrenching dialogue scene that says so. Likewise the family’s acoustic version of “Sweet Child of Mine”: tear-jerking to some, cheeseball to others.

It took me some time to adjust to the scale of the plot as I watched this film. The very first scene, in which Bo kills a deer in a gruesome fashion during a family hunt, and his father anoints him a man for doing so, creates the expectation that we’re going to see something more epic and violent, some independent film iteration of Gangs of New York even. In retrospect I suppose he was merely establishing that this family was beyond Mendocino, this was not a lifestyle revolution, but a revolution-revolution.

My friend Joe Krings edited Captain Fantastic. I know he’d be upset if I said how superb the editing is. Editing, like funeral attire, should never call attention to itself, and that’s more than a passing compliment. I’ve always thought editors are like morticians or maybe taxidermists: Once it’s shot, it’s dead, and it’s up to the editor to make it look alive. Ideally you don’t notice the editing, and that must have been difficult achieving just that with all the multiple-person conversations, and hand-held cameras, taking place.

It’s heart-breaking watching revolutions die out, and watching the smug get smugger. Kudos to Frank Langella (as always) for bringing some humanity to the villainous father-in-law. It’s no laughing matter, not this summer.