Written by Chris Chibnall
"Lost causes are my speciality."
| Episode Title | Premiere Date |
| Once, Upon Time | 14/11/2021 |
On a planet that shouldn’t exist, in the aftermath of apocalypse, the Doctor, Dan, Yaz and Vinder face a battle to survive.
| Character | Cast |
| The Doctor | Jodie Whittaker |
| Yasmin Khan | Mandip Gill |
| Dan Lewis | John Bishop |
| Bel | Thaddea Graham |
| Azure | Rochenda Sandall |
| Swarm | Sam Spruell |
| Vinder | Jacob Anderson |
| Diane | Nadia Albina |
| Fugitive Doctor | Jo Martin |
| Joseph Williamson | Steve Oram |
| Grand Serpent | Craig Parkinson |
| Sonya Khan | Bhavnisha Parmer |
| Old Swarm | Matthew Needham |
| Karvanista | Craige Els |
| Awsok | Barbara Flynn |
| Passenger | Jonny Mathers |
| Police Officer | Chantelle Pierre |
| Voice of the Cybermen | Nicholas Briggs |
| Voice of the Mouri | Amanda Drew |
| Priest Triangle | Nigel Richard Lambert |
| Role | Crew |
| Writer | Chris Chibnall |
| Director | Azhur Saleem |
| Producer | Pete Levy |
| Executive Producer | Chris Chibnall |
| Executive Producer | Nikki Wilson |
| Executive Producer | Matt Strevens |
