Warning! The following contains spoilers for the Doctor Who Season 12 episode "Spyfall: Part 2." Read at your own risk!
The Doctor was able to outsmart the Master once again, though at the end of "Spyfall: Part 2," it's really hard to determine who got the last laugh. While the Master was trapped in the Kasaavin dimension after his plan with the glowy aliens and Daniel Barton went awry, he dropped some knowledge on the Doctor that shook her to the core. Gallifrey was destroyed (again), he was responsible for its destruction, and he supposedly had a valid reason for doing it?
Typically the Doctor is not one to subscribe to the Master's lies, but the phrase the "Timeless Child" triggered a flashback that took her to the scene Doctor Who where fans first heard it back in Season 11. The Master learned of a "lie" related to that phrase that made him so angry, he destroyed the home world he and the Doctor grew up on because of it. So, what does the Master know that viewers don't?
It's a great question, as while the Master assured the Doctor the answer would anger her just as much as it did him, he wasn't about to make things easy for his old rival. The Doctor will have to search for answers herself, and given that the "fam" (Ryan, Yaz, and Graham) is finally demanding questions about her past, it looks like Season 12 will explore this question in depth. Doctor Who will likely explore some bit of the Timeless Child mystery, and hopefully uncover that "great lie" the founding fathers of the Time Lords passed down.
It's an interesting hook for the season, though experienced Doctor Who fans may be leery of trusting the Master at his word. This new guy is no Missy, and this whole reveal came in the midst of the the Master and the Doctor trying to outsmart each other through time. The Doctor ultimately outsmarted the Master because of his arrogance, and he's currently stranded in the Kasaavin dimension. Fortunately for him, he left the Doctor with a question she doesn't have the answer to.
The Doctor likes answering questions, and she's currently on a collision course with a story told to her by the Master. It's certainly convenient he has the answers she needs. The Doctor isn't immediately going to find a method to free her rival, though one could imagine if she gets desperate it might just happen. The Doctor would do anything for Gallifrey; perhaps she can restore it once again?
Of course, the secret of the Timeless Child could be completely legit as well. Chris Chibnall has made some major changes to Doctor Who already, so it's not a stretch to believe he'd do something new with the powerful Time Lords. The real question is how the Doctor will respond to the secret, because it's hard to think of any reveal where she and the Master would agree that Gallifrey deserved annihilation. Let's hope answers come in time!
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