This article is a recap of Netflix’s Black Mirror episode “Men Against Fire.” There are spoilers and discussion regarding the episode’s plot.

Late in “Men Against Fire,” a military psychiatrist (Michael Kelly, who plays Doug Stamper in House of Cards) tells young soldier Stripe (Malachi Kirby) that most soldiers don’t actually shoot to kill. Instead, they fire above the heads of their enemies.

Given the title of the episode, it’s clear he’s repeating the argument of a book called Men Against Fire: The Problem of Battle Command, published in 1947 and written by World War I vet and World War II combat historian S.L.A. Marshall. The book, based on interviews Marshall conducted with soldiers immediately after combat, claims that during WWII, only one in four US soldiers in combat actually fired at their enemy with the intention of killing them — despite their training. The Army, Marshall argued, should increase its effectiveness and invest its resources in training its infantry to shoot to kill.

Empathy is a mark of humanity, the psychiatrist tells Stripe, and “that’s a good thing — until your future depends on wiping out the enemy.”

Like most Black Mirror episodes, “Men Against Fire” is set in a near future where the promise and optimism of 20th- and 21st-century technologies have been gamed out to their frightening but queasily logical conclusions. According to the show, if the technocrats have their way, humans’ faulty wiring — bugs, if you will — will be systematically replaced with fixes that aren’t really fixes at all, but ways to strip us of our humanity. Black Mirror presumes that we will eventually — and voluntarily — “upgrade” ourselves out of being human.

Black Mirror is the bleakest possible picture of a post-human world. But interestingly, “Men Against Fire” — while it lacks some of the tension and terror of other episodes — ends in a profoundly chilling place that has nothing to do with our future and everything to do with our past.

Who’s the real zombie?

In “Men Against Fire,” we’re at first led to believe that the bug of this episode is some kind of virus that turns people into zombie-like beings called roaches. Stripe and his fellow soldiers are sent to a shantytown in the midst of a forest, where the villagers’ food supply has been pilfered and contaminated by these roaches. The villagers plead with the soldiers to protect them, and the soldiers promise to help.

The soldiers board a truck headed for the home of the local oddball, known to be deeply religious and, probably, harboring roaches in his home. And so he is. As Stripe’s commanding officer sits downstairs with the man, by turns mocking his beliefs and trying to convince him that the only humane thing to do is wipe out the roaches, the soldiers canvass the house. Eventually, Stripe finds the roaches upstairs, huddled and in hiding. Their faces are flattened and insect-like and their teeth razor sharp; he shoots them and stabs one repeatedly even after he’s dead.

But then Stripe picks up an object the roach had been waving at him, a small wand that emits a bright green light, and when he looks into it, he hears a high-pitched scream.

That high-pitched scream keeps returning, giving Stripe a headache. It becomes more pronounced as time goes on. The headache can pretty much be ignored, but it interferes with his PT and he’s sent to the sick bay for a checkup, where the psychiatrist declares that Stripe’s “implants pass every diagnostic.”

“Let’s get you a good sleep tonight,” the psychiatrist says, typing into his computer. “A real good sleep.”

The “real good sleep” the psychiatrist promises Stripe is an amped-up version of his usual dream, which features a beautiful young woman we’ve assumed, to this point, is his girlfriend or wife. But it looks like the implants, not the soldiers’ brains, are generating the dreams. The night after the checkup, Stripe’s implant apparently isn’t fixed, and it gets glitchy, multiplying his visions of the woman (who is no longer somewhat chastely clad in lingerie but stark naked).

When he wakes up in a cold sweat, he sits up in his bunk and looks across the room. All of the soldiers lie on their backs, like corpses in a row, tucked neatly into their blanket, completely still save for their fingers, which are moving rapidly in accordance with their dream.

“Ah!” I wrote down at this point. “They’re the real zombies.”

“Men Against Fire” lacks some of the tension of Black Mirror episodes

By now we’ve started to figure out what’s going on, which makes “Men Against Fire” feel like a middling Black Mirror episode when considered as pure narrative. It’s not all that riveting for most of it, because you feel like you’ve figured it out while there’s still a lot more of the hour-long runtime to go. The final twist happens too late to build narrative tension, and doesn’t have the shock factor of some other episodes because it’s so familiar.

The best Black Mirror episodes (like its infamous first episode, “The National Anthem,” which turned out to be startlingly true to life) are shocking not because of their bleakness but because they go places you can barely imagine. But “Men Against Fire,” having already leaned on familiar zombie tropes — the fear of outsiders, the question of who counts as human — gives you tools to guess what’s going to happen next. In zombie stories, only a few things can happen from here: Our hero is subsumed by the zombies, or he discovers the zombies aren’t what they seem to be, or he learns to empathize with them.

In the end, in “Men Against Fire,” it’s some combination of all three. The real bug, it seems, was the soldiers’ sense of human empathy. And so the implant was created as a tool of control, a way to weaponize humans, and, most importantly, a way to keep them from hesitating when faced with the enemy.

The roaches’ device that Stripe picked up, we eventually learn, was reverse-engineered by the roaches in order to deactivate the soldiers’ implants. We learn this first when Stripe begins to see roaches’ faces not as the feral, zombie-like visages, but as human faces. We learn it a second time when the psychiatrist explains it all to Stripe, reveals to him that he chose to have the implant, knowing its consequences, and paints it as an important way to “protect the bloodline,” since roaches carry diseases and commit crimes. (Why these people in particular have been deemed roaches isn’t exactly obvious; it seems they’re of Russian or Eastern European extraction, so perhaps a war has erupted and immigrants are being eliminated, but this isn’t the episode’s concern.)

“Men Against Fire” is less about our future and more about our past

By now “Men Against Fire” is dragging up every heinous crime against humanity from the past century: the Holocaust, internment camps, mass incarceration, and attitudes toward the poor that depend on the idea that poor people are just naturally worse than everyone else and that the future of the human race depended on wiping out the blight.

Many of these things, historians warn us, happen because ordinary people turn a blind eye, choosing to see others as less or other than human. (The religious man hiding roaches in his home is almost certainly modeled on the people who hid Jews in their homes from the Nazis.) In other words, atrocities happen because people convince themselves to turn off their empathy.

That’s what’s most startling about this episode, which draws on these shameful histories. It’s not so surprising to imagine a military systematically and technologically removing soldiers’ empathy so they can fight better, by making their targets seem like animals that need to be eradicated rather than people. What is shocking, disturbing, and all too plausible, given recent history, is that ordinary people — civilians who don’t receive implants — don’t see roach faces: They just see human faces on their enemies. But they’re still content to have them brutally murdered by soldiers.

Evil, the episode suggests, is not banal. It’s purposeful. What the soldiers are doing is reprehensible, but controlled; on the other hand, civilians have evolved themselves away from empathy without technology at all, in order to “protect the bloodline.” The implant in the episode is almost a red herring, because by calling up the bloody last century both in its title and in its rhetoric, “Men Against Fire” doesn’t warn against the future so much as recall the past.

So here’s the episode’s real Black Mirror twist: We don’t need technology in order to brutalize the other. We’re plenty capable of it all on our own.

Black Mirror season 3 is currently streaming on Netflix. Read the rest of our episode reviews here.