In the immortal words of David Tennant’s 10th Doctor: What? What? WHAT?!
In "Fugitive of the Judoon," Doctor Who's fifth episode of the season, not only did a familiar hero from the Tennant era return, but writers Chris Chibnall and Vinay Patel also slipped in a brand-new version of the most famous Who character of all time and space. Whether you're a longtime fan or a newbie, the return of one companion and the appearance of another "new" character will leave you with that same scrunched-up face Jodie Whittaker’s 13th Doctor gets when she’s mega-confused.
What does all of this mean? Let’s jump into the complex and sometimes contradictory Doctor Who canon to sort out the big twists in "Fugitive of the Judoon." Geronimo!
**Spoiler Warning: There are massive spoilers ahead for "Fugitive of the Judoon." Stop now if you haven’t seen it. Seriously.**
In order to put the big mysteries of this episode in context, let's ease into how all of this happened. The episode begins as an adventure where the Doctor will tango with the rhino-space police for hire called the Judoon. The first appearance of the Judoon was in Season 3, Episode 1, "Smith and Jones," in which the 10th Doctor met Martha Jones (Freema Agyeman) for the first time when the Judoon transported an entire hospital to the moon. The 13th Doctor's jokes about "a platoon of Judoon near the moon" and "a platoon of Judoon by the lagoon" reference the 10th Doctor making the same rhyming jokes in "Smith and Jones."
Though mainly thought to be employed by the galactic regulatory group called Shadow Proclamation ("The Stolen Earth, "The Magician's Apprentice"), the Judoon have no specific agenda and are hired guns who will seemingly work for anybody. In fact, the 11th Doctor even employed some Judoon in the makeshift army that assaulted Demon's Run in Season 6, Episode 7: "A Good Man Goes to War." The fact we later discover that these Judoon are working for the Time Lords echoes the idea that they've been hired by the Doctor before.
Captain Jack Harkness
If you started watching Doctor Who with Matt Smith’s 11th Doctor in 2010, there’s a very real chance you have no idea who Jack Harkness actually is or why his return in this episode is such a big deal. Though he’s alluded to during the 11th Doctor era in "The Wedding of River Song," and the 12th Doctor briefly dreamed of Jack in the penultimate Peter Capaldi episode, "The Doctor Falls," the actual character of Captain Jack — as played by John Barrowman — hasn't appeared in Who canon since the 2011 spin-off miniseries Torchwood: Miracle Day, which is effectively the fourth season of that series. And Captain Jack hasn't appeared in an episode of Doctor Who since the 2010 David Tennant swan song, "The End of Time Part 2."
Jack first showed up on Doctor Who later in the Season 1 two-parter "The Empty Child" and "The Doctor Dances," where he met Rose Tyler and the 9th Doctor. Jack traveled in the TARDIS until the end of that season, and in the Season 1 finale, "The Parting of the Ways," Rose Tyler accidentally used the Time Vortex to turn Jack in a permanent immortal. After that, Jack was zapped back into Earth's past, where he eventually became the de facto leader of Torchwood 3, a branch of the alien-hunting organization Torchwood.
Torchwood had its own TV series from roughly 2006-2011, with a few network changes and gaps between. Notably, Jack's character has always been presented as either bisexual or pansexual — he flirted with the 10th Doctor and kissed the 9th Doctor on the mouth. This is referenced outright when Jack kisses Graham (Bradley Walsh) on the mouth in this episode, believing Graham to be a regenerated new version of the Doctor.
At this point, we have to assume this version of Jack comes chronologically after the last time we saw him on Earth in Miracle Day, but because Jack also has had access to time travel and is immortal, that's not entirely clear. Before he joined Torchwood, Jack was a "Time Agent," which meant he had a wrist-operated vortex manipulator called "cheap and nasty time travel," by several characters. We've seen this exact tech used by a lot of characters since then including the 11th Doctor, River Song, Missy, and most recently by the evil Krasko in the Season 11 episode "Rosa."
In "Fugitive of the Judoon," Jack doesn't seem to be wearing his vortex manipulator at all and has stolen a low-rent spaceship instead. This would check with a line from "The Day of the Doctor," where Kate Stewart (Jemma Redgrave) told Clara Oswald (Jenna Coleman) that the Black Archive snagged a vortex manipulator from Jack Harkness "on the occasion of his death... well one of them." Jack is basically impossible to kill, so it seems likely he was never in any real danger in this episode, but then again, some of his super-healing abilities were slowed-down during the events of Miracle Day, and it's not clear where he's at with that particular superpower.
Finally, Jack has a "cheesy" sense of humor, something that Ryan (Tosin Cole) calls "good cheesy," in this new episode. This echoes a similar joke made by former companion Mickey Smith (Noel Clarke) in "Journey's End" when he called Jack "Captain Cheesecake."
"Beware the lone Cyberman"
Although Jack doesn't get to actually meet the 13th Doctor in this episode, he does give Team Tardis a warning for the Doctor: "Beware the lone Cyberman... don't give it what it wants." In trailers for this season, we've seen this lone Cyberman, but the idea that there are "Cyber Wars" in the future of humanity isn't actually new at all. In Season 7, Episode 12: "Nightmare in Silver," the Cybermen are in a full-on war with humans and have chased them to the moon. And, in a super-obscure tie-in video series called "Captain Jack's Monster Files," Jack himself says he knows what happens in the future Cyber-Wars.
Jack also mentions the "Alliance," which he says sent something back in across time and space. This could refer to a group called "The Alliance of Races," which originates in the Doctor Who comic books in the 12th Doctor adventures called "Gangland" and "Terraformer." In that series, an Alliance was created by Rassilon, Lord President of the Time Lords, to combat the Hyperions, but then, later, also pretty much anything or anyone who could stop "harmony."
It's not clear if this is the same Alliance or not, but the fact that the Time Lords are involved and teaming-up with the Judoon means it's somewhat similar.
A new, secret incarnation of the Doctor
Obviously, the biggest news in the episode is the mind-blowing introduction of a new version of the Doctor played by actress Jo Martin. Right now we have no idea if this Doctor is in the 13th Doctor's past or her future, but neither version remembers the other one. Though this character thought she was "Ruth," a human living on Earth, it was later revealed to be a ruse. This Doctor was in disguise using a Chameleon Arch, tech that used by both the Doctor and the Master in Season 3. In the Season 3 two-part episode "Human Nature" and "Family of Blood," the Doctor thought he was "John Smith," had hidden his true personality inside of a fob watch, but here, this Doctor stored her memories in an abandoned lighthouse. (The Master also thought he was a kindly person named "Professor Yana" in the episode "Utopia.")
The 13th Doctor confirms that they are "the same person," and they have "the same brain." But, if the Jo Martin-Doctor is Jodie Whittaker's future self, then Jo Martin should remember having been her. And obviously, the 13th Doctor should remember having been this Doctor if it was in her past. But, there are a few things that suggest this is either a past Doctor or even an alternate Doctor from an alternate past.
For one thing, this Doctor doesn't use a sonic screwdriver, which echoes the 1st Doctor mocking the sonic screwdriver in "Twice Upon a Time." The interior of the TARDIS also looks a lot like the 1st Doctor's TARDIS, which means that it's possible this version of the Doctor predates the William Hartnell version. In the opener of this season, The Master implied the Doctor and the Master had had their memories erased by the Time Lords, so it's reasonable to assume that there are versions of the Doctor that the Doctor somehow has suppressed.
Weirdly, there is a canon precedent for the idea that the Doctor has versions of themselves that predate what we've seen on screen. In the 1976 Tom Baker 4th Doctor serial "The Brain of Morbius," it was made clear there were a lot of mystery Doctors. Back then, when the Doctor was stuck on the planet Karn, the Doctor's brain was probed by Morbius who revealed that there were Doctors that existed well before the four we'd seen up until that point. Several faces splashed across the screen, and the Doctor himself implied there may have even been more.
For the most part, "The Brain of Morbius," has been ignored by Doctor Who canon, because of the notion that the Doctor could only regenerate 12 times had stuck so firmly with most of the series writers over the years. And yet, the Doctor was given a new regeneration cycle in "The Time of the Doctor," which means it's possible this cycle could have been rebooted before, too.
There's also one last part of the puzzle that definitely proves this new Doctor is a real version of the famous Time Lord. In 2018, Russell T. Davies wrote a novelization of his own Doctor Who episode, "Rose." In the TV version, a character named Clive has gathered information about the Doctor throughout history, mostly connected to Christopher Eccleston's 9th Doctor. But, in the 2018 book version of the story, Clive also has images of the 13th Doctor and "a tall... black woman with a flaming sword."
The new Jo Martin Doctor doesn't have a flaming sword, but she is a tall POC and she has a laser rifle. Meaning, it's possible, that this version of the Doctor has been planned out for at least a few years. And regardless if this Doctor is from the distant past or the far future, one thing is clear: we haven't seen the last of her.