The second half of the Doctor Who Season 12 premiere dropped some major bombs, setting off ripples in the Who universe that could change the show forever. It all began in “Part One,” of course, when “O” (the brilliant Sacha Dhawan) revealed himself to be The Master, another Gallifreyan who has served as one of the Doctor’s primary antagonists since Classic Who days. In “Part Two,” The Master’s plan to wipe out humanity alongside tech CEO Daniel Barton and the Kasavin alien race fails, but he still manages to devastate the Doctor, revealing to her that their homeworld of Gallifrey has been decimated. When the Doctor travels back to Gallifrey in the TARDIS, she discovers that the Master is telling the truth. His hologram message explains further: it was he who did it. Why? To get back at them for their lies, says the Master. “They lied to us,” the Master’s hologram tells the Doctor. “The founding Fathers of Gallifrey, everything we were told was a lie. We’re not who we think. You or I. The whole existence of our species, built on the lie of The Timeless Child. Do you see it? It’s buried deep in all our memories, in our identity.” “If you know [head writer] Chris [Chibnall], nothing is there to trick you,” says Whittaker. “He’s a very satisfying writer, but he isn’t necessarily going to give you everything all at once and have it all written out for you in this amount of episodes, if you see what I mean. But I suppose it’s reveal that it’s been mentioned again in episode two just highlights that it’s not a happy accident.” This isn’t the first time Doctor Who has mentioned “The Timeless Child.” The phrase was first uttered last season in “The Ghost Monument.” The alien race known as the Remnants (strips of fabric who were trying to kill the Doctor and her friends) went into the Doctor’s mind and discovered her greatest fears. “Afraid of your own newness,” the Remnants said. “We see deep though. Further back. The Timeless Child.” The Doctor reacted strongly, but the phrase was not brought up again… until now. When the Master’s hologram mentions The Timeless Child, we see flashes of the Doctor’s memory: a shot from “The Ghost Monument” and a child standing in front of a towering structure, a fiery light above it. “Spyfall: Part Two” was an episode that saw the Doctor very casually demonstrating her ability to alter others’ memories, which doesn’t feel like a coincidence in an episode that also suggests there is a secret buried deep in all Gallifreyans’ memories. But what could that secret be? And who is The Timeless Child? While some have theorized that The Timeless Child is either the Doctor or the Master, at this point, it could be anyone—including a character we have yet to meet. NuWho has spent very little time on Gallifrey, with “The Day of the Doctor” and “Hell Bent” the only episodes of NuWho diving into Gallifreyan life and culture in any real way. While NuWho began with the plot foundation that Gallifrey had been destroyed in the Time War, “The Day of the Doctor” backtracked on that and revealed that Gallifrey had not been destroyed but rather hidden in a pocket universe. The episode ends with the first twelve Doctors coming together to save the planet. With the Master’s apparent destruction of Gallifrey, the Thirteenth Doctor has something in common with her earlier, ninth incarnation, who was actively grieving his planet. While Gallifrey may still technically be there (even if it is a burning pile of rubble), should Thirteen follow the mystery of The Timeless Child, she would have to dive into the search for the alleged foundational lie of the Time Lord race while also mourning her home. Sounds emotional, and I am here for it. Who or what do you think The Timeless Child is? Let us know in the comments below… Keep up with Doctor Who season 12 news and reviews here. Kayti Burt is a staff editor covering books, TV, movies, and fan culture at Den of Geek. Read more of her work here or follow her on Twitter @kaytiburt.