SPOILER ALERT: Do not read if you have not yet watched the “Black Museum” episode of “Black Mirror’s” fourth season.

Like the 2014 “White Christmas” episode of “Black Mirror,” Season 4’s “Black Museum” tells three mini stories that tie together in the end. But unlike “White Christmas,” “Black Museum” ends on an upswing for its protagonist, who avenges the father who had been left to be tortured inside Rolo Haynes’ (Douglas Hodge) titular roadside attraction.

“The win is something you root for, and you’re happy when it happens, but it’s still quite dark. I’m sure Charlie [Brooker, writer and executive producer] would never use this term, but I actually think there’s something quite spiritual about the show,” says “Black Museum” director Colm McCarthy. “I think there’s something very touching and genuine to it.”

“Black Museum” starts simply enough, with a young woman (Letitia Wright) stopping to charge her car in the desert and seemingly stumbling upon the museum that houses all kinds of tech twisted by nefarious human desires. The collection includes the tablet with which Sara’s mother once spied on her in Season 4’s “Arkangel” to dresses worn by Yorkie and Kelly in last season’s Emmy winner “San Junipero.”

“There are Easter eggs, not just for this season but all the previous seasons as well. If you really start to go through it, you’ll find references for every single episode, right back to the first ever one,” McCarthy says. “A lot were slipped in by designer Joel Collins, so we had a lot of fun playing ‘spot the reference.’ I’m a massive fan of ‘Black Mirror’ so for me, doing something that was an ode to the show itself was a lot of fun and easy to get my head around.”

Rolo selects a few previously never-seen items to spotlight as he gives his visitor a tour of the space. This allows the episode to dive into the journey of a doctor who worked with a device that allowed him to feel his patients’ pain and therefore diagnose them quicker and more accurately — only to then become addicted to the pleasure the pain brought him. It also provided the chance to explore a story about a young mother whose husband Jack (Aldis Hodge) transferred her consciousness from her comatose body first into himself so she could still watch their child grow up but then into the inanimate object of a teddy bear when it became too much to have her in his head. And finally, it tackled the tale of Clayton (Babs Olusanmokun), a man sentenced to death for a crime he might not have committed and then put on display as the main attraction.

“All of these ideas represent the ludicrous things that humans do to themselves,” explains McCarthy. “The idea of medical tech and surgery tech is quite interesting because a lot of people would love to know exactly what it feels like to be inside somebody else’s body and experience their points of view, and what Charlie does really well is take ideas that we all kind of mull over in an idle way and bring them to their natural conclusion, which is usually actually nightmarish.”

All of these individual elements had to have their own distinct looks but still fit together well enough to form one cohesive story. Because of this, McCarthy considers “Black Museum” one of the harder episodes to direct.

“I’m not a big one for storyboarding and being really specific about every shot, but I do like to make little rules for myself, so we did quite a bit about differentiating,” McCarthy says, noting he worked with Collins to create a unique “palate” per story. “‘Black Mirror’ is sometimes futuristic, but I think a lot of the better ones have the feel of the ’70s, ’80s, ’90s — depending on what part of Charlie’s past and experiences he’s riffing on. We were thinking about American genre films of the early ’90s in terms of the composition of the frames and the color and the filmic quality of the actual image itself.”

McCarthy says he purposely overshot “Black Museum” in order to give himself options in the editing room. “We went backwards and forwards in terms of how we play the relationship in the museum in present day,” he explains. “It was one of those things where we could have spoiled the surprises in the story very easily, but we wanted to enjoy the tension and keep asking good questions about what was happening — dramatically — between the characters.”

Ultimately, what is key to “Black Museum” is not merely the level of sophisticated technology but how it relates to the theme of the episode overall: what it is to experience.

Beyond Jack’s story of leaving his wife’s consciousness in a teddy bear for his child — a toy the child ultimately discarded and that ended up in the museum, still with her trapped inside — Clayton, too, signed over his consciousness so he could live on after death, only to be similarly stuck.

“There are a lot of heavy ideas going on there at the same time,” McCarthy explains. “The idea is being in this cell where all you have is experience with no interaction. I wanted to do something different with this technology than had been done before in ‘White Christmas.’”

But in true “Black Mirror” form, a reveal in the last act of the story showed that the museum’s guest was actually Clayton’s daughter, coming to set her father free and get some revenge on the man who trapped him in a cell worse than jail in the process. McCarthy subtly set up her deeper connection to the theme by having the camera get physically closer to her as the episode went on, bringing the audience into her frame a mind a little bit more each time.

“We shot all of the material from the cockpit first so we could then have a video projector projecting it onto the chair,” he explains. “So, complicatedly, when Rolo’s being electrocuted inside Clayton’s head at the end, you’re seeing what he’s seeing projected onto him while he’s being electrocuted inside the cell, and it’s a big feedback loop of experience.”

“Black Museum” was an ambitious undertaking given that it was shot in about a month and with units that traveled to various corners of the world, including Nevada and Spain, to get footage to elevate the production value. “It was the equivalent of doing an indie feature but quite technologically challenging,” McCarthy notes, “but it was fun and like a puzzle. Everything felt like it had this sort of originality to it.”

“Black Mirror” is streaming now on Netflix.