The Halloween Apocalypse

"The Halloween Apocalypse", prefixed frequently with either "Chapter One" or "Flux", is the premiere episode of the thirteenth series of the British science fiction television programme Doctor Who, and the first part of the six-episode serial known collectively as Doctor Who: Flux. It was first broadcast on BBC One on 31 October 2021. It was written by showrunner and executive producer Chris Chibnall, and directed by Jamie Magnus Stone.