Tzim-Sha survived his encounter with the Doctor at the beginning of the season and has been stranded on the planet Ranskoor Av Kolos for millennia. Like Khan on Ceti Alpha V, he used this time to plot his revenge. He captured and compressed the planets who opposed the Stenza with plans to take Earth next. The technology to condense and house these abducted planets is not stable, and the Doctor warns that he is putting the entire universe in danger.
There have been multiple attempts in Doctor Who to move the Earth, but there is one in particular that has ties to “The Battle of Ranskoor Av Kolos.” While the Sixth Doctor was in court during “The Trial of a Time Lord,” it is revealed that the Time Lords relocated the Earth and renamed it Ravalox. It is relevant to this week, because before Chris Chibnall became the showrunner of Doctor Who, he was a fan and was on television criticizing the season-long arc. You can read more about it from Tread Perilously co-host Erik Amaya here. Clearly, Chibnall has spent the past three decades thinking about how he could take that idea and improve on it.
The central theme this season has been dealing with loss, and in this episode, we see it play out for both Tzim-Sha and Graham. The former struggles with failing against the Doctor, while the latter grieves for his wife who was murdered by Tzim-Sha. Their arcs are counter-points to each other.
Tzim-Sha is consumed by revenge while living in isolation, making a great foil to Graham heal through seeing the universe with the Doctor and bonding with Ryan.
As this season comes to a close, I would have to say that not including any classic monsters was the correct decision. With a complete regime change behind the scenes, it was the perfect palate cleanser for the show to start fresh. It forced Chibnall and crew to earn the audience’s acceptance instead of pandering to nostalgia as a crutch. Jodie Whittaker has been great as the Thirteenth Doctor, and her companions are interesting characters who all have great chemistry. Now that the new iteration is established, I would like to see some familiar elements begin to be reintegrated into the show. Stay away from the Daleks, Cybermen, and Master who have all had a lot of play in recent years. I would really like to see The Rani return, as I think she would be a great arch-nemesis for the Thirteenth Doctor. Driven by scientific knowledge and research, she would fit really well as a dark reflection to Whittaker’s gleeful exuberance for discovery.
Regardless if they choose this direction or not, the show is in good hands, and I eagerly await what comes next.