Unable to return to 14 May 2025, the TARDIS ends up in Miami in 1952. The Doctor (Ncuti Gatwa) and his companion Belina Chandra (Varada Sethu) find a cinema chained shut. At a diner, they speak to the mother of someone who disappeared in the theater. Fifteen people have disappeared like this. The cinema continues to play movies at night. Though much is racially segregated at the time, the waiter allows them to stay at the diner.
Inside the theater, a living cartoon character based on a rubber hose—Mr. Ring-a-Ding (Alan Cumming)—is God of Light, called Lux Imperator. But as a member of the Pantheon of Discord, he is responsible for the missing people. The projectionist, Reginald Pye (Linus Roache) plays films for Lux, who uses his power to recreate Pye’s dead wife.
Lux has trapped the missing people in a film reel and soon traps the Doctor and Belinda and turns them into cartoon characters. When they become sad from not being three-dimensional, they return to normal and go into another false reality. A racist cop accuses them of breaking segregation laws by going to a theater, but they escape through a TV being watched by Doctor Who fans. The fans admit to not being real, but they want to blow up the film reel even if it means their non-existence. They encourage the Doctor and Belinda to defeat Lux.
Lux steals the Doctor’s energy to create a solid body for himself and leave the theater. Belinda tries to burn up the film reels and Pye sacrifices himself. The explosion exposes the cinema to sunlight and Lux expands until he evaporates into the universe, releasing the missing people. Mrs. Flood (Anita Dobson) appears and encourages watching the TARDIS because this is a limited run that ends on May 24. Mid-credits, the three Doctor Who fans, now real, critique the episode.
The episode was written by Russell T. Davies and directed by Amanda Brutchie. It is a mixture of live-action and animation. Critiques praised the entertaining mixture and its references to Who culture. Davies had wanted to do this for a long time but could not get the funding. There were references to pop culture icons like Rock Hudson and Scooby Doo. The mid-credits scene was the first in Who history. The three Who fans were not given surnames until the credits. They were Hassan Chowdry, Lizzie Apek, and Robyn Gossage. They wore Doctor Who merchandise and were real long-term fans. Some of the animators had worked on Roger Rabbit. Ncuti Gatwa and Varda Sethu watched episodes of Scooby-doo to learn the proper movements for cartoon characters.