Doctor: David Tennant
Companion: Catherine Tate – Donna Noble
Others
Bernard Cribbins – Wilfred Mott
Nathaniel Curtis – Isaac Newton
Susan Twist – Mrs Merridew
Daniel Tuite – The Doctor acting double
Ophir Raray – The Doctor beast double
Tommaso Di Vincenzo – The Doctor contortionist double
Helen Cripps – Donna acting double
Production
Directed by Tom Kingsley
Written by Russell T Davies
Script editor: Scott Handcock
Produced by Vicki Delow
Executive producer(s): Russell T Davies, Julie Gardner, Jane Tranter, Joel Collins, Phil Collinson
Music by Murray Gold
Series: 2023 specials
Running time: 54 minutes
First broadcast 2 December 2023
After briefly running into Isaac Newton, where they accidentally replace the word "gravity" with "mavity", the Doctor and Donna find themselves on a very long spaceship at the edge of space where there are no stars, no signs of life and the only mobile thing is a robot the Doctor nicknames "Jimbo", who is slowly walking down the ship's corridor. A voice occasionally declares various words that cause the walls of the ship to move. To fix the TARDIS, the Doctor leaves his sonic screwdriver in the key hole, only for the TARDIS to suddenly disappear. The Doctor tells Donna the TARDIS reset its numerous functions, including its H.A.D.S (Hostile Action Displacement System) function. The TARDIS will only come back once the danger has abated.
The Doctor and Donna get to work on trying to get the ship up and running, but encounter doppelgangers, self-dubbed "Not-Things", of each other. The Not-Things are intelligent, but lack the concept of size and shape and constantly distort and morph into animalistic versions of them. The Doctor and Donna struggle to outwit the Not-Things as they also assimilate their thoughts and way of thinking. The Doctor eventually figures out the ship's captain committed suicide three years ago by ejecting herself into space after setting off a series of actions so the Not-Things could not figure out what she had done. The Doctor realises the announced phrases are a countdown and Jimbo was slowly walking towards a self-destruct button in a last ditch effort to kill the Not-Things.
The Not-Things race to stop the bomb while the Doctor speeds up the countdown. As the danger is about to pass, the TARDIS returns and the Doctor enters it. He nearly takes the wrong Donna, but ejects her after noticing her wrist is 0.06 millimetres too thick and rescues the real Donna just as the ship explodes, killing both Not-Things. The Doctor and Donna return to Camden Market and are greeted by Wilfred Mott, who is overjoyed to see his granddaughter has reunited with the Doctor. However, Wilf reveals the world is once again in danger as people suddenly begin fighting with one another and a plane crashes nearby. The Doctor, Donna, and Wilf take cover against the TARDIS as the crashing plane explodes.
Wild Blue Yonder