It tells the story of Bo (Zazie Beetz), a paparazzi, and Mazey Day (Clara Rugaard), an actress hiding from the media after a car accident.

Brooker wrote it after the sixth series episode "Demon 79", another horror story, and aimed to broaden the scope of the programme.

Set in 2006, the depicted paparazzi pursuit of Mazey was compared to media attention on Britney Spears, Paris Hilton and Lindsay Lohan.

In 2006, a paparazza named Bo (Zazie Beetz) takes photographic evidence at a motel of a male celebrity having an affair with a man.

They harass a celebrity whose sex tape has gone public: Whitty provokes her with misogynistic slurs and threatens legal action when she reacts.

The actress Mazey Day (Clara Rugaard) quits a film shoot in the Czech Republic after a hit and run under the influence of wine and hallucinogenic mushrooms and disappears from the public eye.

Bo, who was confronted by her flatmate Nathan (David Rysdahl) over late rent, tracks Mazey to a film producer's mansion via a takeaway place she mentioned in a magazine article.

Mazey, tortured by flashbacks, smashes up the living room overnight and Dr. Babich (Kenneth Collard) arranges for her to stay at a New Age rehab for the weekend.

Brooker said this episode, labelled as Red Mirror, helped him find a new perspective for the series, closer to "people are fucked up" than "tech is bad".

[10] In writing "Mazey Day", Brooker considered "The National Anthem", the first episode, which "was obviously designed to be startling and surprising and weird".

[13] First reports in July 2022 revealed the casting of Zazie Beetz, Clara Rugaard and Danny Ramirez, who played Bo, Mazey Day and Hector, respectively.

[16] The local newspaper Diario Sur reported in that month that a Black Mirror episode was being filmed in the Spanish province of Málaga, under the name "Red Book".

[18] Framestore worked on visual effects for the werewolf, including rigging for a digital double of Rugaard transforming into the creature.

[19] The company NVIZ provided compositing of graphics such as computer and television screens and worked on redesigning Málaga backgrounds to resemble Los Angeles.

Ramirez commented that "the system itself" is at fault: while Hector or Bo invade people's privacy, they are forced to make money to pay rent.

[32] Reviewers compared Mazey to Paris Hilton or Lindsay Lohan, subjects of immense paparazzi attention in the early 2000s.

[33][27] In Den of Geek, Juliette Harrisson said "ruthless paparazzi ... taking photographs of an injured or dying woman" resembled the death of Diana, Princess of Wales, which is referenced in "Loch Henry".

[34] The Independent's Louis Chilton compared the death of Caroline Flack to the celebrity suicide from Bo's photograph and media coverage.

[35] Like "Loch Henry", the episode criticises mass media and shows characters pursuing knowledge that leads them into danger.

[24] Writing in The Verge, Andrew Webster compared Bo's enticement into chasing Mazey to a heist film trope of convincing criminals into "one last job".

[28] Mazey plays "Supermassive Black Hole" by Muse, which is prominently used in The Twilight Saga, a film series about werewolves and vampires.

Vanity Fair's Richard Lawson said it would have been more relevant 15 years ago, with Armstrong and The Independent's Nick Hilton concurring that the subject matter was heavy-handed and dated.

[35] Esquire's Rachel Dodes described the moral as "trite" and i's Emily Baker said it was "already widely accepted" that a "ferocious appetite" for celebrity unhappiness was wrong.

[46] In IGN, Samantha Nelson contrasted it with From Dusk till Dawn (1996), saying the latter had a successful tonal shift but "Mazey Day" undermines its twist "by trying to make its final moments emotionally stirring".

Bojalad reviewed that there was "exactly the correct amount" of foreshadowing, including Mazey's driver's rivet gun and the rehab setup.

[33] With ambivalent reactions, Baker said the twist was not bad but lacked inventiveness or novelty, while Webster found the last shot "fitting" but "a little on the nose".