The ending to Doctor Who season 12 makes some huge reveals, including answers to the Timeless Child mystery, and brings about some major changes to the BBC series. Doctor Who season 12, which once again stars Jodie Whittaker as the Doctor and has Chris Chibnall as the showrunner, has largely been defined by its many running mysteries. From the surprising return of the Master in the season 12 premiere, the show has placed questions atop riddles wrapped inside enigmas.

Be it the Timeless Child, Brendan, the Lone Cyberman, or Ruth aka the Doctor, Doctor Who season 12 has built up a lot of storylines revolving around keeping the Doctor - and audiences - largely in the dark over what’s really going on. With Doctor Who season 12’s finale, “The Timeless Children”, it was time for at least some of those questions to be answered.

Chibnall wasn’t interested in neatly tying up every running plot thread, leaving some instead for Doctor Who season 13, but he does nonetheless provide some big, game-changing explanations. Here’s what happens in Doctor Who season 12’s ending, and what it means.

The Doctor Is The Timeless Child

The mystery of the Timeless Child has been at the very core of Doctor Who season 12. Even before then, it was setup with a brief mention in season 11, but this year it has underpinned the new run of episodes since the premiere, “Spyfall”. There, fans were given a tantalizing hint of what was to come: that there was a Timeless Child, a mystery person from Gallifrey who was removed from Time Lord history, but the reveal of which would change everything the Doctor knew about her past.

While there were various theories about who the Timeless Child may be, in the end it was the most obvious the came to pass: the Timeless Child is the Doctor. The Timeless Child was a young girl found by Tecteun, a Shabogan who left Gallifrey to explore other planets. She found the Timeless Child at the boundary to another dimension, and brought her to Gallifrey, where she died but, to Tecteun’s surprise, regenerated. This regeneration, and the subsequent ones the Timeless Child went through, would form the foundation for everything to come from the Time Lords of Gallifrey.

At some point in her life cycle, the Timeless Child regenerated into the being who would become the Doctor. The memories of all these past lives were redacted from the Gallifreyan Matrix, with the Doctor instead starting anew. That’s why she remembers being a child on Gallifrey and the previous regenerations she’s been through, but nothing of those that came before. This is the biggest retcon yet to the Doctor’s origin: she’s not a Gallifrey Time Lord, but something much, much more, a Timeless Child from an unknown place who was the beginning of the Time Lords themselves. As well as this, it makes the idea of the Doctor’s regeneration cycle - which came to an end with Matt’s Smith’s Doctor, before being granted a whole new set - rather moot, as the Timeless Child, not being a Time Lord, has unlimited lives - of which she lived at least seven before William Hartnell’s “First” Doctor. Fragments of this story were hidden in that of Brendan, the immortal Irish police officer whose life had parallels to the Doctor; these splices of imagery were left behind by Tecteun, perhaps, as the Master suggests, as an apology or gift to the Doctor for all that had happened, and a clue to figuring it out.

Of course, much of this is still left unexplored by Doctor Who season 12’s ending. We still don’t know where the Timeless Child originated from, or how and why she had regenerative powers in the first place, so there’s likely more to come there. And at the same time, the Timeless Child reveal, supposed to completely destroy the Doctor, ultimately has the opposite effect: she is even greater than previously thought, but at the same time doesn’t need to be defined by the past anyway

Ruth & The Division Are Still Big Mysteries

While the Timeless Child mystery is, for the most part, wrapped up by the end of Doctor Who season 12, some other questions don’t get so neatly answered, not least those of Ruth and the Division, two of the other major setups yet to be paid off. Prior to the reveal that the Doctor is the Timeless Child, the identity of Ruth was season 12’s most shocking plot twist. That there was another incarnation of the Doctor, from an unknown point in the timeline, was and still is rather massive. While Ruth (Jo Martin) returns when the Doctor is within the Matrix, and the Doctor herself asks the questions the audience has been wondering about her origin and where she fits in, there are no answers provided. Was Ruth among the pre-Hartnell regenerations? Is she another secret regeneration, perhaps between the Second and Third Doctors? Or is there another big twist coming to explain just how this Doctor fits into the cycle?

Likewise, the Division too remain something for future episodes to deal with. As the Time Lords continued to evolve as a society, and with previous efforts at intervening in other galactic goings-on not ending well, the race chose to no longer get involved in the matters of other races. Not everyone agreed with this approach, however, and so the Division was formed, effectively serving as a clandestine, black-ops group for Time Lord intervention. It was to this group the Timeless Child was assigned, working on the Division’s behalf to alter events. The Division is presumably an early version of what will eventually become the Celestial Intervention Agency (CIA), a Time Lord organization who, like the Division, are tasked with carrying out covert operations across history.

That’s something ripe for future exploration, because most of what the Division did is redacted from the Matrix. It’s after the Timeless Child is recruited that the story cuts out and all that’s left are the flashes of Brendan. The Division were the ones to alter the Doctor’s memories and remove the data from the Matrix, but there are still some serious blanks to be filled in regarding what they actually did, and how the Timeless Child served them (and why they ultimately had to wipe his memories).

The Doctor’s Companions Are Returned To Earth

Unsurprisingly, the Doctor largely wins the day in Doctor Who season 12’s ending, with the fate of the universe secured and her companions returned safely to Earth thanks to a TARDIS found on Gallifrey, which actually has a working chameleon circuit, and so disguises itself as a house. It’s a fitting place to leave things for the Doctor’s “fam” right now, for a few reasons. They’ve been journeying around with the Doctor for quite some time, so it does make sense that they now get the opportunity to go home, and it’s pretty common for Doctor Who to leave things in this way ahead of fresh adventures the next year. If Doctor Who season 13 wants to shake things up with the companions - there are rumors of Toisin Cole leaving - then it’s well set for that too.

This better fits with the Doctor’s journey as well. The fact that she doesn’t sacrifice herself in the end, but is arrested and put in prison while her companions presumably think she’s gone, should make for bigger narrative payoffs when they are either reunited or, somehow, the companions discover what has happened to the Doctor. They may not be Time Lords, but they do now have a TARDIS of their own, and it would be a bit surprising if we don’t see at least one of the companions behind the controls of this new TARDIS at least briefly in the future. And if nothing else, seeing how Graham, Yaz, and Ryan continue on in the Doctor’s absence and deal with the loss should provide fertile ground for character development.

Are The Master & His Time Lord Cyberman Still Alive?

Doctor Who season 12’s ending pays off the running Cybermen thread by giving them the ultimate upgrade, fusing the Cyberium with the Master in order to create a super race of Time Lord Cybermen, complete with the ability to regenerate. While such powers would’ve meant few could stand in their way, their own genius proved their undoing, with the death particle, the greatest weapon of the Cybermen, used against them. Gallifrey was destroyed by Ko Sharmus, using the death particle and one last explosive, which ostensibly destroys both the Master and his army of Time Lord Cybermen. Or does it?

A general rule with television is that if you don’t see the bodies, then they probably aren’t dead. And sometimes even when you do, that doesn’t mean they’re really gone, especially when it comes to the Master. He’s come back a number of times already, and since he possesses the ability to regenerate, then it stands to reason the Master should be able to return again. The same goes for the Time Lord Cybermen too, at least in theory, although there’s seemingly less narrative reason to have them survive. The Master, though, is the Joker to the Doctor’s Batman, so it seems like a safe bet he’ll be back in some form (and hopefully that means more of Sacha Dhawan’s take on the character). We don’t know just how effective the death particle was, while nearby to the Matrix room we know there were at least two TARDISes, but potentially more. After the Cyberman attack Ko Sharmus, the Master yells at them, saying: “All of you, through here, now!” It’s possible, then, that the Master and at least some of the Time Lord Cybermen were able to make it to another TARDIS and escape Gallifrey’s destruction and the death particle.

Why The Doctor Is Arrested And Put In Prison

While the Master may or may not have escaped in a TARDIS, the Doctor certainly did - but that only led to more trouble. The Doctor was able to get back to her own TARDIS - leaving the other disguised as a tree, perhaps for eternity now - but almost as soon as she entered she cornered by the Judoon, who arrested her and zapped the Doctor away to a galactic prison. As per the Judoon operative who captured her, the Doctor has been sentenced to whole life imprisonment in a maximum security facility, which appears to be stuck in the vast nothingness of space. How she escapes will no doubt be a big feature of Doctor Who’s next episode(s), but there’s also the matter of why she was arrested by the Judoon.

The clearest answer is because the Judoon, as seen earlier in season 12, had been hired to capture the fugitive called the Doctor, which in that case was Ruth Clayton. Ruth had been working for Gallifreyan enforcers but run away, leading to the Judoon being hired to bring her in. At the end of Doctor Who season 12, they capture Jodie Whittaker’s Doctor, but this is in effect the same thing: both Ruth and Thirteen are iterations of the Doctor, and so Whittaker’s version was also the same fugitive. This further links the two Doctors together and provides even greater confirmation that they’re the same. Given Ruth was working for Gallifrey, it’s even possible that she had ties to the Division at some point (or the CIA), and this angle develops that story.

At the same time, it’s not impossible there are more timey-wimey shenanigans at play here. We still don’t know where Ruth fits in, and it isn’t entirely impossible she comes after the current Doctor. The Judoon who captures the Doctor is the same one who failed to do so in “Fugitive of the Judoon” and had her horn removed for doing so - that’s grown back by the time of her appearance in Doctor Who season 12’s finale, but it’s not beyond comprehension those events took place in the future.

The Daleks Return In The Next Doctor Who Episode

Doctor Who season 12’s ending has one final sting, with the confirmation that the Doctor will return in “Revolution of the Daleks”, which also means that the Doctor’s biggest foes are coming back as well. The Daleks haven’t featured much yet in Jodie Whittaker’s run as the Doctor, with just the one appearance in the 2019 New Year Special, “Resolution”. There, the Dalek had attempted to return to Skaro and lead a new invasion of Earth, but was ultimately cast into a supernova by the Doctor. Still, it’s impossible to keep the Daleks away for too long, and in what’s another holiday special (whether Christmas Day or New Year) they’ll be back.

“Revolution of the Daleks” promises a much bigger story for the classic Doctor Who villain, both in terms of scale and their importance to the arc of season 13. The “Revolution” in question likely means the Daleks rising up once more and aiming for dominance of some kind, perhaps because they know that the one person who can stop them is behind bars, and it could be this Dalek attack that leads to the Doctor escaping (or even being freed from) prison. Either way, the Daleks and the Doctor are set for a big showdown after Doctor Who season 12’s ending.

Next: What To Expect From Doctor Who Season 13