"Lux" is the second episode of the fifteenth series of the British science- fiction TV series Doctor Who , written by Russell T Davies and directed by Amanda Brotchie. It premiered on April 19, 2025
. In this episode, the Fifteenth Doctor, played by Ncuti Gatwa, and his companion Belinda Chandra (Varada Sethu) land in 1952 Miami while trying to return to 2025. They investigate a mysterious cinema where fifteen people have disappeared. Inside, they confront Lux Imperator (voiced by Alan Cumming), an animated god of light and member of the Pantheon of Discord, who traps them in film and turns them into cartoon characters. The Doctor and Belinda eventually escape by burning the film reels, causing Lux to expand infinitely and release the trapped people. The episode is notable for mixing live-action and animation and includes meta-references and fourth wall breaks
. The story explores themes such as racial segregation in 1950s Miami and the fictional nature of the Doctor Who universe, contrasting real-world issues with the show's imaginative worlds. The episode also reflects on the show's place in modern pop culture and its evolving relationship with its audience
. "Lux" received positive critical reception for its innovative use of animation and storytelling, despite recording low broadcast ratings initially
. A novelisation by James Goss is scheduled for release in July 2025
