Last night, Doctor Who fans bade farewell to the 13th Doctor, Jodie Whittaker. Regeneration episodes have tended to be very big in scope, with rapidly-increasing dangers and seemingly impossible odds, and The Power of the Doctor was no exception. I should warn that spoilers will be riddled throughout this post, so please don’t read if you haven’t watched the episode, and have plans to do so.

The Doctor ends up being confronted by an alliance of her three most infamous, dangerous foes. The Cybermen (led by the Master’s Cyber Timelord hybrids), the Daleks, and the Master himself team up to take down the one enemy they hate more than each other. The Master is running the show, and has promised much to his new allies. As always, the trap for the Doctor is quite elaborate, and as always, the Master, Cybermen and Daleks don’t take advantage of the chance to simply kill her. Instead, the Master has a plan to force the Doctor to regenerate into the Master, so he can effectively masquerade as the Doctor, and ruin their legacy. This act will also erase the Doctor forever, and meanwhile, the Master has hatched a scheme to take out UNIT from the inside, playing upon former companion Tegan, to infiltrate the facility with Cybermen.

We have an episode filled with guest stars. We get, as mentioned, Tegan, played by Janet Fielding (she travelled with the fifth Doctor). Ace (Sophie Aldred), who once travelled with the seventh Doctor, returns as well. Bradley Walsh is back as Graham, and we get cameos from previous Doctors (including David Bradley as William Hartnell’s first Doctor, and Peter Davison, Colin Baker, Sylvester McCoy, Paul McGann and Jo Martin all appear). The end of the episode features several other former companions, including Mel Bush (Bonnie Langford), Jo Jones (Katy Manning) and original cast member Ian Chesterton (97-year-old William Russell). As such, Doctor Who, in the BBC’s centenary year, honours its roots in a pretty epic way.

Perhaps though, what the episode needed was more of the 13th Doctor’s relationship with Yaz (Mandip Gill). Not for the first time, the Doctor has kept a companion at arm’s length, owing to complicated feelings and the ever-present risk of travelling through space and time (John Bishop’s Dan leaves the Doctor at the start of the episode, after a close brush with death). The episode touches upon the wishes of both to remain adventuring together, but by episode’s end, the Doctor is wounded, and we know what that means. Feeling that things would not be the same, the Doctor and Yaz part ways, and the Doctor regenerates.

In Jodie’s place is not Ncuti Gatwa (the actor lined up as the 14th Doctor), but instead, in a twist (albeit a widely-known twist), David Tennant, who played the 10th Doctor. He is quite confused to have regenerated into a previous Doctor, but knowing the Doctor’s life, they won’t have time to consider what just happened. There is the briefest of teases for the next adventure, but The Power of the Doctor is not about what happens next. It’s a celebration of what made 13 unique, including a thorough commitment to her friends, and a determination to preserve life, even among her enemies.

Alongside Ms Whittaker’s departure, Chris Chibnall also said farewell, ahead of Russell T. Davies’ return. Mr Chibnall’s turn as showrunner has been regarded as a mixed bag, but some of the episodes are among the most powerful the series has ever produced. ‘Rosa’ was an incredible and emotional experience. ‘Spyfall’ was a lot of fun, and ‘The Haunting of Villa Diodati’ was genuinely creepy. Any appearance from Sacha Dhawan’s manic Master was memorable. The Flux concept was clever and gave us the return of the terrifying Weeping Angels in ‘Village of the Angels’.

Mr Chibnall also subverted Doctor Who history, and not every fan is happy about that. For 50+ years, the accepted lore was that William Hartnell’s Doctor was the first incarnation of the iconic Timelord, but the introduction of the Timeless Child story dramatically altered this. It now seems that the Doctor has had numerous previous lives, which were hidden from her, to protect a secretive and manipulative organisation called ‘Division’. Whether any of these concepts will be explored further is unclear, as Russell T. Davies might have his own ideas.

Whatever happens, Jodie Whittaker will always have the distinction of playing the first female Doctor, and for appearing in some of the show’s most memorable and exciting stories. Hopefully she will appear again!