The title of the longest-running science fiction show ever is also a question without a question mark. Back in the Matt Smith Eleventh Doctor era of Doctor Who, that phrase — "Doctor ... who?" — was metafictionally established as the "the First Question, the oldest question in the universe, that must never be answered, hidden in plain sight." But now, 57 long years of very complicated canon and two incarnations of the Doctor later, Doctor Who has finally answered its most basic question.
Who the heck is the Doctor anyway?
In the Season 12 finale, "The Timeless Children," the Doctor's (Jodie Whittaker) oldest nemesis, the Master (Sasha Dhawan), reveals a huge secret about her past, one that gives the most famous time traveler of them all a brand-new origin story.
**SPOILER WARNING: Spoilers ahead for Doctor Who Season 12, Episode 10, "The Timeless Children."**
Like many Doctor Who season finales before it, "The Timeless Children" is jam-packed with more stuff than the episode could possibly address. And the biggest revelations are without a doubt directly connected to a brand-new backstory for the titular character. Prior to this season, for the most part, Who canon always floated the idea that the various incarnations of the Doctor began with William Hartnell's First Doctor in the original version of the show in 1963, starting with "An Unearthly Child." And, other than the Fourth Doctor episode "The Brain of Morbius," secret versions of the Doctor that predated William Hartnell simply didn't exist. In fact, in the final Peter Capaldi episode, "Twice Upon a Time," the Twelfth Doctor made peace with his original face and even encouraged the First Doctor's own regeneration, right before eventually becoming Jodie Whittaker's Thirteenth Time Lord.
It's hard to believe that was only two seasons ago, because now, not only is William Hartnell's First Doctor no longer the First Doctor, but the Doctor themself is officially the very first "Time Lord" ever. Not only that, but there was a whole cycle of regenerations prior to what we've been aware of for the past 57 years of Who canon.
Some of this, however, isn't exactly news, but instead a very detailed explanation of what we already learned in Episode 5 of this season, "Fugitive of the Judoon." In that episode, we met a mysterious new version of the Doctor (Jo Martin) who had disguised herself with a Chameleon Arch and was living as a human named Ruth. She'd had her memories briefly repressed as to who she really was. But now we know who the "Ruth" Doctor was: just one of many regenerations the Doctor had before her memory was erased by the Time Lords, and — at some point, we don't know when — turned into William Hartnell's "First Doctor." During this time, the Doctor was part of something called the Division, which operated outside of the Time Lord's rules of interfering with the affairs of other planets. In essence, the secret life of the Doctor was similar, philosophically, to why the "original" Doctor stole a TARDIS and left Gallifrey, thus embarking on the journey of the Doctor we've always known.
Weirdly, this was hinted at the aforementioned crazy Fourth Doctor episode, "The Brain of Morbius," in which various past faces of the Doctor were shown to be buried in their memory. And, toward the end of "The Timeless Children," when the Doctor weaponizes all her Doctor-ish memories against the Matrix, we briefly see the faces of the "Morbius Doctors," which seems to establish that, yes, a perceived "mistake" in old-school '70s canon is now pretty much the basis for this entire new premise.
However, in the new episode, the Doctor initially rejects this new info, ranting, "I know my life! I remember my growing up!" The Master assures her, "All that happened. It just wasn't your first life." By this he means it wasn't her first cycle of 12 regenerations, something the Master explains was artificially built in by the earliest Time Lords, who weren't actually Time Lords.
And that's because there's a much bigger reveal than the Doctor just having had a whole separate set of lives before the series even began in 1963.
No. The deeper revelation of the entire episode is that the basic essence of Time Lord physiology — that whole ability to regenerate into new bodies — was actually stolen from a singular mysterious alien being, a stranded child rescued by an explorer named Tecteun. Before they were ever called Time Lords, the natives of Gallifrey were known as Shabogans. This episode explains that the Shabogans only rebranded themselves as Time Lords after incorporating the Regeneration ability into the genetic code of all future generations. And the person they stole that genetic code from was a forgotten version of the Doctor. The Timeless Child.
So, what exactly did the Doctor do during that entire period of time after being the Timeless Child but before having their memory erased and turned into William Hartnell?
The bottom line is, we don't know exactly how many regenerations the Doctor had before becoming the classic version, but it's pretty damn clear the Jo Martin "Ruth" Doctor obviously comes from that gap. And, even though the Doctor does get a mind-chat with the "Ruth" Doctor here, the answers aren't going to be found in the database known as the Matrix. When the Doctor and the Master inhabit the Matrix in this episode, the Master notes that entire sections have been "redacted" and replaced with a more generic memory. (These were the "Brendan" scenes from the previous episode, watered-down versions of the Doctor's time working for "The Division.")
Speaking of the Time Lord Matrix, on almost every single level, "The Timeless Children" is a direct sequel to the Fourth Doctor Tom Baker story "The Deadly Assassin." Airing after "The Brain of Morbius" (but in the same year!), this 1976 serial is where almost all of our previous assumptions about this Time Lord mythology come from originally. And, as in "The Timeless Children," that serial featured the Doctor and the Master squaring off in the Matrix. Plus, the Master also mentions "assassinating presidents" and the location of the Panopticon, all events and places established in "The Deadly Assassin." In fact, the entire 12-Regeneration rule comes from "The Deadly Assassin," too.
"The Timeless Children" also solves the comment made by the Remnants about "the timeless child," way back in 2018, in the Season 11 episode "The Ghost Monument," when the Thirteenth Doctor was just getting started. Why those flying, evil scraps of paper were aware of the great lie perpetrated by the Time Lords is unclear, nor is it clear how many other alien species may or may not be aware of this grand deception. Will future seasons of Doctor Who reveal more about these missing pieces of faux-Time Lord history? What about the other Doctors? And how is the Doctor going to get out of this Judoon prison?
All of these questions are tantalizing, and there are good bets to be made that future Who seasons will tackle each one in turn. Plus, we're almost certainly seeing Jo Martin's Doctor again at some point. That said, perhaps the most interesting revelation in "The Timeless Children" was simply the fact that the Doctor's origin is now even more mysterious than it was before. This is a show about time travel, meaning that the past is often just as vital as the future. But now we don't actually even know which alien race the Doctor/the Timeless Child really belongs to. She was an orphan — possibly from another dimension — and already had the ability to regenerate. All the Time Lords copied her.
So, we may have found out more about who the Doctor is, but bizarrely, we no longer know what she is. The show isn't going to rebrand as Doctor What, but considering the massive fake-out from the Time Lords, maybe it should.
Doctor Who Season 13 does not yet have a release date. The next episode of Doctor Who will be the New Year's Day 2021 special, "Revolution of the Daleks."