All is darkness. We’re somewhere in Mexico, outside, in the middle of the night. The man before us is a meth cook, his face mostly covered by a bandana, lit with only a flashlight. An assault rifle hangs over his shoulder. “We know we do harm,” he’s saying. “But what are we going to do? We come from poverty. If we were doing well, we would be like you.” What does he mean by that? What does he think we’re like? We’ll meet this guy again at the end of the movie, and learn more about him, more than we may have wanted to know. In the interim, we’ll meet some other people too — a Mexican surgeon who mobilized his townspeople to take up arms against a brutal drug cartel; a self-appointed border patroller who did likewise in Arizona — and the experience of getting to know them will feel like wading into fetid quicksand. “All we want is justice,” says a grieving woman with tears in her eyes. She tells a terrifying story of broad-daylight mass murder, of babies grabbed by their ankles and smashed against rocks. Justice seems impossibly far away from this forsaken place, where cartel terrorism has been answered with vigilantism, and apparently the only constant in life is the slow creep of corruption, a force of nature as unavoidable as gravity. Cartel Land chronicles ancient patterns of power abuse playing out in an irreversibly modern world. As a documentary, it’s pretty damned depressing. As a parable of human nature, it’s vital.