Others
Sacha Dhawan – The Master
Patrick O'Kane – Ashad
Ian McElhinney – Ko Sharmus
Julie Graham – Ravio
Alex Austin – Yedlarmi
Matt Carver – Ethan
Rhiannon Clements – Bescot
Seylan Baxter – Tecteun
Kirsty Besterman – Solpado
Paul Kasey – Judoon Captain
Nicholas Briggs – Voice of Cybermen & Judoon Captain
Matthew Rohman – Cyberman
Simon Carew – Cyberman
Jon Davey – Cyberman
Richard Highgate – Cyberman
Richard Price – Cyberman
Mickey Lewis – Cyberman
Matthew Doman – Cyberman
Paul Bailey – Cyberman
Jo Martin – The Doctor
Production
Directed by Jamie Magnus Stone
Written by Chris Chibnall
Script editor: Fiona McAllister
Produced by Nikki Wilson
Executive producer(s) Chris Chibnall, Matt Strevens
Incidental music composer: Segun Akinola
Series 12
Length: 2nd of 2-part story, 65 minutes
First broadcast 1 March 2020
The Master persuades the Doctor to join him on Gallifrey, where he forces her to enter the Matrix. He shows her the secret history of Gallifrey and its native Shobogans. Tecteun, a space explorer, found a "timeless child" with infinite capacity to regenerate. She adopted the child and studied her, successfully grafting her regeneration capacity into the Shobogans, transforming them into Time Lords; they chose to limit a Time Lord's regenerations to twelve. The Master reveals that the Doctor is the "timeless child". Tecteun and the child were inducted into a clandestine organisation called the Division, the details of which were redacted from the Matrix. The Doctor's memories were subsequently erased, prior to the childhood she remembers; only snippets remain, masked as the story of the Irish policeman Brendan.
With the Doctor trapped in the Matrix, the Master lures Ashad to Gallifrey and shrinks him with his tissue compression eliminator, taking the Cyberium. With its knowledge and the bodies of the Time Lords he had shrunk on his arrival to Gallifrey, the Master creates a race of infinitely-regenerating Cybermen, aiming to use them to take over the universe. In the Matrix, a vision of the Ruth Doctor gives the Doctor a means to escape by overloading the Matrix with all of her memories from her past regenerations.
On board the Cyber-carrier, Bescot is killed, while Yaz and Graham successfully hide from the invading Cybermen in empty Cyber-armor. They subsequently save the lives of Ryan, Ethan, and Ko Sharmus from Cybermen forces sent to the planet by Ashad. The group gather and agree to go through the portal to Gallifrey.
The Doctor regroups with her companions, and discovers Ashad's minaturised body contains a "Death Particle" capable of destroying all organic life on a planet. The Doctor and her friends blow up the Cyber-carrier, destroying Ashad's army in the process and foiling his plot to rebuild the Cyber-Empire. Finding unused TARDISes, she programs one to take her allies home. The Doctor takes one of Ko Sharmus' explosives to set off the Death Particle. She is unable to trigger it when goaded by the Master, but Ko Sharmus appears and takes it, as penance for failing to suitably hide the Cyberium. The Doctor escapes in another TARDIS as the explosion consumes Gallifrey.
The Doctor's allies arrive on contemporary Earth in their TARDIS. The Doctor lands the other TARDIS near her own, but as she prepares to take off, she is arrested by the Judoon and teleported to a prison located inside an asteroid.
The Timeless Children