Doctor: Jodie Whittaker
Chris Noth – Jack Robertson
Harriet Walter – Jo Patterson
Nathan Stewart-Jarrett – Leo Rugazzi
Nathan Armarkwei-Laryea – Armen
Helen Anderson – Rachel
Nicholas Briggs – Voice of the Daleks
Barnaby Edwards – Dalek Operator 1
Nicholas Pegg – Dalek Operator 2
Sharon D Clarke – Grace
Directed by Lee Haven Jones
Written by Chris Chibnall
Script editor Fiona McAllister
Produced by Alex Mercer
Executive producer(s) Chris Chibnall, Matt Strevens
Incidental music composer Segun Akinola
Running time 71 minutes
First broadcast 1 January 2021
In 2019, shortly after the destruction of the Reconnaissance Scout Dalek, the damaged casing from it is transported to a government facility but intercepted en route. Using the Dalek parts, businessman Jack Robertson funds a defence drone resembling a Dalek to suppress public riots and gave some to politician Jo Patterson to use in her constituency.
In the present day, 10 months have passed since Graham, Ryan and Yaz returned to Earth. Graham and Ryan meet Yaz at the TARDIS they returned in, which is disguised as a house in a neighbourhood, where she is investigating the whereabouts of the Doctor. Graham shows her a leaked video of the defence drone demonstration and they unsuccessfully confront Robertson about the drones.
Patterson, projected to be elected the Prime Minister, requests Robertson to increase the drone production so they can be implemented nationally. Scientist Leo Rugazzi discovers organic cells in the Dalek remnants and clones the cells into a living creature. Before he can incinerate the creature, it escapes and takes control of Leo's mind and body. Dalek-controlled Leo travels to Osaka, Japan, where Dalek clones are being grown in a facility.
The Doctor has been imprisoned in a distant asteroid for a number of decades. She eventually encounters Jack Harkness, who learned of her arrest and committed a series of crimes in order to rescue her. He uses a temporal freezing gateway disinhibitor bubble to take them both to a vortex manipulator he previously hid in another cell, which transports them back to the Doctor's TARDIS. The Doctor rejoins her companions and learns about the new Dalek threat. Jack and Yaz investigate the facility in Japan while the Doctor, Graham, and Ryan confront Robertson. They all meet back up in Japan where the Dalek reveals its plan to take over Earth. Using ultraviolet light, the Dalek clones transport themselves into the defence drones which begin exterminating humans.
The Doctor sends out a Dalek reconnaissance signal, which reaches a death squad of Daleks. The death squad Daleks eliminate the reconnaissance Daleks because they do not consider them pure Dalek due to their having traces of human DNA. Roberston, impressed by their intelligence, decides to make an alliance with the Daleks and reveals that the Doctor actually summoned them. Jack, Graham, and Ryan infiltrate the Dalek ship to rig it with explosives. The Doctor tricks the Daleks into the other TARDIS where it is set to collapse on itself and be transported to the Void to be destroyed.
Jack elects to stay on Earth for a while and spend some time catching up with Gwen Cooper. While the Doctor suggests resuming her travels with her companions, Ryan chooses to stay on Earth and Graham elects to remain with his grandson. They sadly part ways with the Doctor, who gifts them with psychic paper. The Doctor and Yaz continue their adventures together while Ryan and Graham decide to use their new psychic paper to investigate strange phenomena on Earth.