While Black Mirror started out as a series exploring the myriad terrifying ways technology could impact our lives, it has since grown into a more general genre anthology. It’s nice when episodes have that techno focus, but it’s no longer a necessity. Case in point: “Demon 79,” a season 6 story that’s pure classic horror homage. Its premise wouldn’t be out of place in a collection like Tales From the Crypt or Cabinet of Curiosities. But don’t let the lack of Black Mirror-ness dissuade you — this episode is a blast of Hitchcockian scares with just the right kind of twist.

“Demon 79” — which was directed by Toby Haynes and written by Ms. Marvel’s Bisha K. Ali and Black Mirror creator Charlie Brooker — is centered on Nida (Anjana Vasan), a woman living a quiet, boring life in a small town in 1970s northern England. She works as a clerk at a shoe shop, doesn’t drink or ever really go out, and is constantly subjected to overt racism from her co-workers: a boss asking her to eat lunch somewhere else because of the smell or a fellow clerk openly reading anti-immigration pamphlets at work. She never speaks up for herself, just meekly goes about her day. But she has sharp, violent fantasies about murdering those who wrong her, including a local creep who’s become infamous for strangling his wife.

So it’s actually kind of handy when, one day on her lunch break — which now takes place in a dingy basement, you know, because of the smell — she comes across a demonic talisman and accidentally awakens it with her blood. This ropes her into a contract: she has to partner up with a very chatty demon named Gaap (Paapa Essiedu) and kill three people over the next three days. If she doesn’t, well, it’s armageddon time.

There have been countless stories about people forced to kill a few in service of the many, and demon-assisted revenge fantasies aren’t particularly new, either. But “Demon 79” still manages to find its own unique voice, mostly by mashing up the chilling nature of Nida’s grisly errand with some welcome comic relief. Watching her go about her task is genuinely stressful. At first, you almost hope she’s at least going to get some catharsis out of it, using this opportunity to go through with her dark fantasies. But the reality of murder isn’t so easy, and — even though she steadily becomes more comfortable with the idea — her kills are neither smooth nor simple. I mean, her weapon of choice is a hammer. That always leads to some splatter. Over the course of the 74-minute episode, you can see and feel her turn into something else, and, while she morphs quite a bit, the transition feels completely natural.

Things also get more complex as she’s forced to deal with the surprisingly bureaucratic rules put down from the overloads in the demonic realm. Gaap is there to guide and encourage her, but he can’t help much; he’s an invisible presence who only Nida can see, hear, and speak to. (This has the side effect of making her look appropriately unhinged in public.) He also provides most of the much-needed tonal relief. Despite living inside an ancient object activated by blood, Gaap is talkative and cheerful and presents himself to Nida in the form of a famous singer decked out in fur and platform boots. It’s not so much that he’s cracking jokes the whole time, but he adds a ray of positivity that helps lighten things up at just the right moments. This is particularly true of the ending, which, in proper Black Mirror fashion, is genuinely surprising.

So no, “Demon 79” isn’t the kind of Black Mirror story that will make you recognize (yet again) that your smartphone is actually bad for you. But that’s okay: it shows how the series has grown into something more expansive, where even a horror homage can fit alongside the more traditional sci-fi stories. You never quite know what to expect, keeping viewers guessing — which is just as much a part of Black Mirror as all the dark futurism.

Black Mirror season 6, including “Demon 79,” is streaming on Netflix now.