Black Mirror: “The National Anthem” opens with British Prime Minister Michael Callow learning before dawn that the beloved Princess Susannah has been kidnapped. Four close advisors, including Home Secretary Alex Cairns, arrive at No. 10 Downing Street to show Callow the ransom video, in which Susannah reads out the demand that Callow have sex with a pig on live television that afternoon at 4 p.m. Callow learns that the video, which was uploaded to YouTube, has been proliferating on the Internet faster than the government can take it down; the public already knows everything.
Although the government imposes a D-notice publication ban on the story, the story trends on Twitter, leading CNN to report on it. After that, the UKN broadcaster disregards the D-notice and begins all-day coverage of the story. Meanwhile, the home secretary secretly assigns a special agent to see if they can fake footage using a porn actor's body and chromakey (green screen) special effects.
As the story spreads, UKN interviews people on the street and conducts official polls. When Callow's wife, Jane, learns what is happening and how people online are making fun of the prime minister, she is angry that the world is laughing at them. Their conversation is interrupted by a phone call from the queen, who pressures Callow to do whatever he can to get the princess back safely. After a young aide tracks the original YouTube upload to an abandoned building, Callow believes they've found the kidnapper's hideout. Relieved, he orders a raid.
Adult film star Rod Senseless arrives at the TV studios so he can perform as Callow's body double with the pig. On the way in, Rod is recognized by a man who snaps a photo on his phone. Meanwhile, a staff member confides in Callow that most members of the public do not expect him to fulfill the kidnapper's demands. However, UKN receives a severed finger and a thumb drive with a video ostensibly showing the princess's finger being removed as a punishment for breaking his rules. Callow learns only then about the attempted faking, and that the kidnapped found out about it because the photo of Senseless made the rounds online. Callow nearly strangles the home secretary for her blunder.
Once people see video of the princess's finger being severed, public sentiment shifts: now eighty-six percent of voters believe Callow must meet the kidnapper's demands. With only an hour to go before the 4 p.m. deadline, Callow orders police to raid the kidnapper's hideout. However, it turns out to contain only a decoy mannequin. Having received a tipoff from a No. 10 staffer, the UKN journalist Malaika is inside the building, filming the raid on her phone. When she runs from the police, they shoot her in the leg and then shoot her phone.
With no other options, members of Callow's staff say he has to go through with it; otherwise, the public will despise him and the princess will be killed because of him. The home secretary implies that his security detail may also turn on him, leaving him and his family vulnerable to revenge attacks.
On the drive to the TV studio, Callow ignores his wife's calls. On his way in, he swallows a Viagra. Cairns advises him to not ejaculate too soon, as the public might perceive it as enjoyment; he is told to take as long as he needs to finish. He enters the closed set, where there is a roving camera operator and boom operator. A sedated, docile sow stands eating from a dish of food.
The broadcast begins with a tone designed to nauseate viewers and make them not continue watching; however, no one is dissuaded, as shots of the empty city streets are shown. Callow approaches the pig, saying tearfully that he loves his wife. He removes his trousers and mounts the pig while everyone in the country watches with some mix of amusement and horror on their faces.
The sex act goes on for over an hour. Meanwhile, a police officer finds Princess Susannah lying in the middle of a pedestrian bridge over the Thames River. The viewer sees an artist in white overalls hang himself in his studio. His right hand is bloody and bandaged; he is missing a finger.
After the Prime Minister finishes, he vomits in a toilet at the studio. Cairns receives a call and learns about the princess's safe return. However, she learns the princess was released at 3:30, and had been stumbling around central London. No one noticed because everyone was inside watching the spectacle. Cairns realizes the kidnapper was making a moral statement about humanity's desire for humiliation. She tells the staffer to destroy the reports about it, saving the prime minister from the knowledge that he went through with the sex act needlessly.
The episode ends with a UKN news report from one year later. On the anniversary of the humiliation, Callow is more popular than ever, with soaring public approval ratings. He and his wife are shown making an appearance at a school gymnasium. Both are smiling. The reporter comments on how the kidnapper was Carlton Bloom, a former Turner Prize–winning artist, leading some to speak of the terrorist act as "the first great artwork of the 21st century," which 1.3 billion people took part in.
The news report ends with footage of Callow and his wife walking into No. 10 Downing Street. Once inside and away from the cameras, Jane scowls at her husband and walks upstairs without him, leaving him to hang his head in shame while he stands at the bottom.
