"Lux" is the second episode of the fifteenth series of the British science- fiction television series Doctor Who , which premiered on April 19, 2025
. The episode was written by Russell T Davies, the showrunner, and directed by Amanda Brotchie
. It stars Ncuti Gatwa as the Fifteenth Doctor and Varada Sethu as his companion Belinda Chandra
. In "Lux," the Doctor and Belinda land in 1952 Miami, Florida, while trying to return to 2025. They investigate a mysterious abandoned cinema where fifteen people have disappeared. The episode features a unique blend of live- action and animation, with the antagonist Lux (also called Mr. Ring-A-Ding), an animated godlike character voiced by Alan Cumming, who traps them inside film
. The story explores themes such as racial segregation in 1950s Miami and meta-commentary on Doctor Who itself, including fourth wall breaks and reflections on the show's place in popular culture. The episode has been praised for its innovative use of animation and its thoughtful engagement with social issues and the nature of the Doctor Who universe
. A novelisation of the episode by James Goss is scheduled for release in July 2025
