This year will be the final season for not only series star Peter Capaldi (the 12th Doctor) but for longtime showrunner Steven Moffat as well. The final two-part episode of the season, which will be titled “World Enough and Time”/”The Doctor Falls”, will feature the return of John Simm (Life on Mars) as the Master. Michelle Gomez, who plays the latest (and first female) Master, known as Missy, is also signed for the episode. What will happen when two versions of the most evil Time Lord share the screen?
Simm last played the Doctor’s nemesis in the 2009 episode “The End of Time” part 2. In that story, the Master ended up trapped, along with the Rassilon and the Time Lords, in the Great Time War. However, we know that in the 50th anniversary special, “Day of the Doctor”, the Doctor saved his home planet Gallifrey by relocating it. When the Master returned as Missy in 2014, it was implied that the Doctor unwittingly freed the Master/Missy while saving Galifrey.
We don’t know the details of what happened to the Master after he was sealed in the Great Time War with the Time Lords, but we know Rassilon was not happy with him at that point. We also don’t know how The Master escaped, and what the circumstances were that led to him regenerating into Missy.
Steven Moffat likes to fill in the gaps of Doctor Who continuity. For instance, when the show returned to the airwaves in 2005, fans were left to speculate about how the 8th Doctor (Paul McGann) regenerated into the 9th Doctor (Christopher Eccleston). It wasn’t until the 50th anniversary in 2013 that we learned about the missing incarnation of the War Doctor (John Hurt.) So, it’s possible that this episode could tell us the untold story of how the Master became Missy. Although Moffat promises that the two versions of the character will come “face-to-face”, that doesn’t mean we still can’t see the regeneration. This show is about time travel, after all.
Along with the two incarnations of the Master, the Doctor will also have to deal with the return of the original versions of the Mondas Cyberman, who have not been seen since the Patrick Troughton (2nd Doctor) era, in the 1960s. (I wonder if they’ll still have those odd sing-song voices.)
There have been several multi-Doctor stories but there has never been a multi-Master tale, so this should be an interesting two-parter to wrap up Capaldi and Moffat’s final season. Capaldi and Moffat’s official last episode will be the 2017 Christmas Special, which will introduce the 13th Doctor.