It's become a Christmas tradition of mine, that after spending the whole day with the family, opening gifts and eating way too much food, that I settle down that evening to watch the Dr Who Christmas Special. Plus, as an added bonus, this episode will be the last of Peter Capaldi and the introduction of Jodie Whittaker. It's also the last episode for Steven Moffat as show-runner, but more about that later.
In this episode we see the 12th Doctor and the 1st Doctor team-up to stop....well really nothing. This episode is them literally deciding on if they should regenerate or just die. Oh, there is a "glass being" that they are first trying to stop but then realize that the "glass being" is actually good and that really this whole episode is a waste of time. Throw in a couple cameos and a not-so shocking surprise at the end, that the Captain's last name is "Lehtbridge-Stewart", and there you have probably the worst regeneration story ever. The previous episode of series, "The Doctor Falls" is how Peter Capaldi should have went out. That was a fantastic story, with excitement, emotion and the Doctor sacrificing his life to save people he hardly knows. Instead, we got 2 Doctors acting like kids who don't want to clean up there bedrooms.