In Doctor Who's Season 2 finale, "The Reality War," the Time Lord learned that Fourteen's "bi-generation" was a result of his life force desperately trying to find a way to survive and continue his species.
While setting out to rescue Poppy, his daughter created through a wish, the Doctor poured his own regeneration energy into the Time Vortex, triggering a regeneration. In doing so, he shifted reality so that she could continue to exist as the human daughter of Belinda (which, tragically, meant she was no longer his daughter, as well).
His regeneration did follow, with Ncuti Gatwa's adventurer transforming into a female Doctor with Billie Piper's face. She previously played Rose Tyler in the series and was once exposed to the heart of the TARDIS as "Bad Wolf." That and the fact that she wasn't introduced as the new Doctor has led to speculation that this is a temporary change before the new Doctor is properly introduced.
Much has been said about Doctor Who Season 2 ending with a less definitive regeneration before Piper was cast, or, had one not happened at all, then we'd have gotten a happy ending with the Doctor and his friends gathering at a party (a scene featured in trailers). Gatwa would've continued playing the Time Lord heading into Season 3, but in reality, couldn't remain committed to the show indefinitely when Hollywood is calling.
In a major tease for the future, the Doctor's granddaughter, Susan, was set to be shown from afar alongside Poppy, referring to her as "mum," and confirming that the time-traveller now had a family. Still, with the show's future so uncertain, Russell T Davies decided on a less open-ended conclusion.
Now, actress Carole Ann Ford, who plays the Doctor's granddaughter, has revealed that she shot these scenes with the intention of further exploring Susan and Poppy's link to the Time Lord down the line.
"You didn’t see the episode, which was to sort of introduce my coming back, where I was holding hands with a beautiful little tiny black child [Sienna-Robyn Mavanga-Phipp], three years old," she recalled (via SFFGazette.com). "And we were watching through the window somewhere where the audience wasn’t supposed to know where we were supposed to be."
"And we were watching by a newly-embodied grandfather, who was now Ncuti [Gatwa], and watching him have a wonderful time singing and dancing in a party in a shop opposite where we were," Ford continued. "And obviously, my character Susan, was longing to just go there and fling her arms around her grandfather and say, 'Grandfather, how lovely to see you after all this time and how did you survive your floating about in space...and why have you changed?'"
"Anyway, that was unfortunately not to be — for reasons I know and will not disclose," she concluded. Davies has instead closed the door on the storytelling potential that the Doctor's daughter and granddaughter have, though the nature of the series means it could somehow be revisited.
Last-minute reshoots completely changed Doctor Who's Season 2 finale, and the fate of the series is no clearer now than it was when this episode aired.
The BBC and Disney+ likely won't announce their plans to part ways until after the spin-off, The War Between the Land and the Sea, airs next year. What becomes of Doctor Who from there is hard to say, though another streamer could get involved. Either way, Davies will likely move on ahead of yet another reboot of the long-running sci-fi series.
What would you like to see from Doctor Who if and when it returns to our screens?