In the Doctor Who 60th anniversary special Wild Blue Yonder, the Doctor and Donna Noble find themselves on an abandoned spaceship at the edge of the universe after an accident aboard the TARDIS. The TARDIS is triggered by the Hostile Action Displacement System (HADS) and flies away from danger, leaving the Doctor and Donna to rely on their wits and the strength of their bond to navigate this predicament.
The spaceship has fallen through a wormhole to the very edge of the universe, and the duo encounters strange entities known as No-things, which originate from the Nothing at the edge of creation. These entities can mimic others, absorbing memories and physical forms, and aim to become perfect replicas to escape from the spaceship. The No-things target the Doctor and Donna, creating imposter versions of both of them. This leads to the development of the Doctor and Donna as characters, revealing new layers to their personalities and pasts.
The story revolves around the Doctor and Donna facing uncomfortable truths about themselves and their past. Donna deals with her fear of being forgotten by her family and the realisation of her own capabilities. The Doctor, confronted by the fake Donna, faces his past actions, including the Timeless Child and the Flux, and grapples with the guilt and emotional vulnerability associated with these events.
The episode’s climax involves the discovery of the spaceship’s captain, who had previously killed herself to prevent the No-things from taking over the ship and wreaking havoc in the universe. This act was intended to hide a slow-moving bomb designed to stop the No-things. The Doctor speeds up the countdown of the bomb’s detonation to stop the No-Things from fully taking over his and Donna’s memories. As the bomb explodes, the TARDIS returns to rescue them, leading to a mix-up where the Doctor initially rescues the wrong Donna.
The episode ends with the Doctor and the real Donna safely aboard the TARDIS, reflecting on their recent experiences. They return to Earth, where they find Wilf in a wheelchair and discover that Earth is in peril, setting up the story for the next special.
Wild Blue Yonder is a character-driven episode, much like series nine, Heaven Sent, where Peter Capaldi carries the whole episode alone. At least in this episode, Tenant and Tate have each other (and their doubles) to play off. The episode focuses heavily on its main characters’ emotional and psychological aspects, coupled with a sense of body horror and existential dread. It raises questions about identity, memory, and the nature of self, all while maintaining the adventurous spirit of Doctor Who.