On the surface, Black Mirror appears to be a pure anthology series – each episode distinct in subject matter, setting and tone. But dig a little deeper and Charlie Brooker's techno-thrillers offer up a hoard of buried treasures – Easter eggs that link each disparate episode together.
"It always used to be that it was just a bit of fun," Brooker has said. "But then sometimes we've done some things where we did explicitly refer to other episodes. I think the rule is that when a character says something that explicitly refers to something else, it's canonical."
So there you have it: everything in Black Mirror is connected. Don't believe us (or Brooker)? Here's the proof.
1. Callow's shame
The first ever episode, 'The National Anthem', saw British prime minister Michael Callow (Rory Kinnear) brutally humiliated by a terrorist and forced to perform sex on a pig to save a young girl's life.
What happens to him next is referenced in season 3's 'Shut Up and Dance': a webpage announces "PM Callow to divorce", with his wife Jane (Anna Wilson-Jones) apparently unable to get over her husband porking a porker.
Things have got even worse for Callow by season 3's 'Nosedive', in which a tweet from the (now former?) PM glimpsed on Lacie's computer reads: "Just got thrown out of the zoo again."
2. Victoria Skillane
Brooker has spoken about his desire to produce a bonafide sequel to season 2's 'White Bear', but he's already put its protagonist Victoria Skillane (Lenora Crichlow) elsewhere in Black Mirror.
In 'White Christmas', a news ticker at the bottom of Joe's television references Victoria, who was an accomplice to fiancé Ian Rannoch's murder of a young girl. Her trial is similarly referenced on a webpage in 'Shut Up and Dance', with news that her latest appeal has been thrown out of court again appearing via news ticker in season 3's 'Hated in the Nation'.
'Hated' also features two more references to Victoria – the episode sees a Twitter hashtag, '#DeathTo', applied to public hate figures, including Skillane, while rookie cop Blue (Faye Marsay) reveals she previously worked on the Ian Rannoch case.
3. White Bear symbol
More from 'White Bear': the symbol on the television in that episode (also the giveaway tattoo which helped the police identify Ian) appears in Joe's prison cell in 'White Christmas' and appears several times in season 3's 'Playtest' as a marking on gaming equipment.
4. Hot Shots
The reality TV contest from Brooker and Konnie Huq's brutal satire 'Fifteen Million Merits' is briefly glimpsed on Joe's television in 'White Christmas'.
And while it's a little blurry, the flashforward which closes season two's 'The Waldo Moment' appears to depict Abi Khan – Jessica Brown Findlay's character from 'Fifteen Million Merits' – on a billboard.
5. Waldo
Speaking of Waldo, that pesky blue bear just keeps on popping up. A sticker featuring the character is glimpsed in 'Shut Up and Dance', while a clip from the late night talk show featured in 'The Waldo Moment' briefly plays (once again) while Joe is channel-flicking in 'White Christmas'.
Also in that festive frightfest, dating coach Matt (Jon Hamm) is seen remotely guiding his socially awkward client Harry (Rasmus Hardiker) on a mission to pick up girls, and one of the users watching the livestream has the username 'I Am Waldo'.
A news ticker in 'White Christmas' also refers to political candidate Liam Monroe's sexting scandal, which again originates in 'The Waldo Moment'.
6. The pregnancy test
Two very similar pregnancy tests appear in season one's stunning 'The Entire History of You' and season two's heartbreaking 'Be Right Back' – they're slightly different designs, but both confirm the imminent arrival of a little bundle of a joy with the same animation of a dancing baby.
7. Sea of Tranquility
Remember that rather odd sequence in 'Nosedive' where Lacie grabs a ride with cosplayers who are fans of the sci-fi show Sea of Tranquility? Back in 'The National Anthem', a special effects expert hired to fake the PM's coitus mentions having worked on the show, describing it as a "HBO moon western".
Given that 'The National Anthem' appears to take place in the present day, while 'Nosedive' features future tech, it's probable that Sea of Tranquility ran for quite a few years. Maybe it's HBO's next big hit filling the Game of Thrones void?
8. Granular
A magazine in 'Playtest' with visionary games developer Shou Saito on the cover also mentions Granular, the same company that built the robotic bees that went rogue in 'Hated in the Nation'.
9. TCKR
That magazine cover is full of secrets. It also advertises a feature on TCKR ("turning nostalgia into a game") – the same tech company maintaining the virtual world seen in Emmy-winning fan favourite episode 'San Junipero'.
10. Shou Saito
The events of 'Playtest' crop up again in 'Hated in the Nation'. One of Brooker's beloved news tickers reals that Shou Saito has launched a new immersive new gaming system, the same one that poor Cooper (Wyatt Russell) was subjected to.
11. MASS
MASS is the codename for the neural implant featured in season 3's 'Men Against Fire', the device which fools Stripe (Malachi Kirby) into persecuting ordinary humans as "roaches".
It's referenced in 'Hated in the Nation' via – you guessed it – a news ticker, which announces that the military are about to put the program into operation (placing this episode as some time before the events of 'Men Against Fire').
12. UKN / Geraint Fitch
Fictional media network UKN appears across multiple episodes of Black Mirror. Martha (Hayley Atwell) receives an e-mail from UKN News in 'Be Right Back', while the network broadcasts the same headline ("Geraint Fitch cleared of wrongdoing following paparazzi scuffle") in both 'The National Anthem' and 'The Waldo Moment'.
