11. Spyfall Part 1
The concluding moments of the first two parter of the Whittaker era is a perfect example of why there should be a lot more cliffhanger endings. The first episode kicks off well enough but loses its way when the spy aspects take over, the motorbike chase proving both underwhelming and silly.
Then in one line, the whole episode turns to brilliance once more. With the Doctor, companions and Agent O all boarding a plane containing the villainous Daniel Barton, a seemingly innocent question towards Agent O is met with the most unexpected response. It is soon revealed that the man in question known as Agent O is actually The Master. The revelation works because it comes as a total shock, while also making perfect sense on a second viewing.
The Doctor is soon vanquished from the plane and trapped in an alien world with seemingly no escape, while her companions are trapped on a crashing plane after the Master detonates a bomb in the cockpit. On top of this, the alien threat introduced earlier remains on the loose while The Master is revealed to be in cahoots with them and Barton, who escaped before the plane took off.
Unlike so many episodes of the 12th season, the episode actually engages the audience and leaves us wanting more. If only we could receive more episodes like this and less preachy nonsense like we've received so far with Whittaker.