Sometimes you just know you’ve got a good one on your hands. Something about the topic and presentation screams professionalism, high quality, riveting subject matter—just the right mix for a can’t-miss experience. And sometimes, you’re just flat out wrong.

Fortunately, that’s not the case with Cartel Land, a documentary produced by Kathryn Bigelow (Zero Dark Thirty, The Hurt Locker) and directed by Matthew Heineman, which is just good enough to make me consider watching Escape Fire, his earlier documentary on the health system in America.

I mean, it might not be the one-sided glop of, say, Michael Moore’s Sicko.

Cartel Land is about two different parts of the world: The Arizona Border in the USA and the Michoacan province in Mexico, both of which are being terrorized by the titular cartels. The bulk of the movie concerns a doctor who raises a vigilante army to free his country from the drug cartels; this is the more interesting of the stories.

The American side is interesting in its own way. In the tony Pasadena theater where I watched it, the rednecks patrolling the border at night were the source of much amusement. Not our sorts of people, those gun-toting, minority-harassing, trailer-dwellers.

I didn’t feel the movie had that tone. Oh, they showed the one guy who was down there because we gotta keep America white, or whatever, but however outré this impromptu border patrol is, there’s no doubt they’re dealing with some bad hombres. And dealing with them because our feckless, sclerotic bureaucracies don’t care to.

But if there’s apathy on the American side, the Mexican side is just a—spoiler alert—dispiriting voyage into sheer corruption. Our doctor is sincere, no doubt. He’s also successful. But success attracts power, both from the cartels and the government—who are, in essence the same thing—and soon a noble movement to save the people becomes a cartel itself.

Our doctor has some ethical problems of his own, too, pedestrian though they are, and it’s a very hard thing to lead a movement that absolutely requires, above all things, a strict code of honor when your own hands aren’t clean.

It’s not a pick-me-up of a film.

But it is interesting: How do you end systemic corruption? There have been corrupt times in many societies, and many societies have pulled out of the spiral to enjoy glorious golden ages—even if they weren’t aware they were living in them.  But you have to have a code, and you have to follow the code, even at the expense of your friends or yourself.

Fascinatingly, there’s an incident on the Mexican side that is, for lack of a better word, murder. The vigilantes stop a guy who has tattoos indicating membership in a cartel. So they interrogate him, then they kill him. (The doctor gives the order; we don’t actually see this.) If they don’t, they know he’ll get 50 of his closest friends to come and kill them.

That’s sub-optimal, to say the least. And not really conducive to a code of honor. But it’s an interest look into genuine powerlessness. (And, as a side note, American media is a happily compliant contributor to the corruption.)

Worth watching twice.