YouTube channel ScreenCrush has amassed a 9-minute explainer of the show’s most major hidden details to date. Some of the Easter eggs—like the news network UKN appearing on TVs in all four seasons—are details you might have noticed after watching a few episodes yourself. Take the pregnancy test from the Jon Hamm episode, “White Christmas.” It’s the same brand as the pregnancy test from season 2’s “Be Right Back.” And the Grain implant, which lets characters block each other in real life (among other things), not only appears in two of the new episodes (“White Christmas” and “The Entire History of You”), it also gets used in season 3’s “Men Against Fire.”
Other details are so minuscule you’ll wonder how they saw them at all. Moving tickers at the bottoms of UKN reports will often mention the names of characters who appear in later episodes, and ad rails on fake websites advertise products you see in later seasons.
All of it supports one big fan theory: Every freaky, futuristic story the show has told so far has been happening in the same universe. But there’s never been a hint conclusive enough to really confirm the theory.
ScreenCrush noticed a pattern of Where’s Waldo-esque details in one season 4 episode that might lay the debate to rest, though.
It turns out the finale episode of season 4, “Black Museum,” is littered with references to each Black Mirror episode to date. You just have to pay close attention to the background. The broken tablet from “Arkangel” is on display in the small roadside museum, as is a honey bee from “Hated in the Nation,” and the bloody bathtub from “The Crocodile Murder.” In fact, it seems every object on display in that exhibit is tied to the plot of a previous episode. The characters even casually mention the technology from “San Junipero” aloud during their tour, as if that’s something they heard about on the news recently. So if this one museum curator was able to track down each of these items for his exhibit, even though none of the characters from different episodes seem to know each other or carry over in any way—not only are these people all definitely in the same physical universe in some capacity, they might all be connected by… something bigger, too.
And just like that, Black Mirror hits us with another twist.