For a show about time travel, Doctor Who certainty likes referencing its own past. And in the season 10 finale, those nostalgic lines and flashbacks eventually, became very literal. With “The Doctor Falls,” the titular Time Lord has officially gone back to the start.

Spoilers ahead for the Doctor Who season 10 finale, “The Doctor Falls.”

There are a lot of twists in “The Doctor Falls,” but the one fans probably didn’t see coming had nothing to do with the Doctor, Missy, the Master, or the Cybermen. Instead, this season’s standout companion, Bill Potts (Pearl Mackie), was given a shocking happy-ending. Remember Bill’s girlfriend from the season opener, “The Pilot?” Well, Doctor Who has never had a more welcome deus ex machina than the sudden reappearance of the watery-alien being known as Heather(Stephanie Hyam). After being turned into a Cyberman, and almost dying on a field of battle with the Doctor, Bill’s fate looked absurdly grim. That is, until Heather materialized out of nowhere, repaired Bill’s body, and got everyone back on the TARDIS. Did it make sense? No. Was it a great and a fitting happy ending for Bill? A big yes.

The basic plot of “The Doctor Falls,” was — like many episodes of late — a kind of amalgamation of previous Who story concepts. Just like with Matt Smith’s final episode — “The Time of the Doctor” — Peter Capaldi is given a similar hopeless and endless battle to fight. And just like “Time of the Doctor,” a force from outside has to save him. In 2013, it was the Time Lords giving the Doctor new regenerations. This time, it was Heather just magically fixing everything. Thinking about how this works will give any fan a headache, but only the very cynical would say that it all didn’t work. “The Doctor Falls” wasn’t trying to be a great or original episode of science fiction television. It was trying to remind everyone why they might love Doctor Who. And, for the faithful, it succeeded.

Essentially, “The Doctor Falls,” is a giant easter egg farm for fans hoping to catch references to the entire show. There’s a barn that is reminiscent of “Day of the Doctor” and “Listen.” Capaldi is offering Jelly-baby candies just like Tom Baker’s 4th Doctor. There are visual flashback to every single contemporary companion of the Doctor, from Rose Tyler to Martha Jones, to Captain Jack, to Amy Pond, and yes…even Clara. (Apparently the Doctor can remember Clara again?)

Instead of writing new lines where the Doctor reflects on regeneration, Steven Moffat uses old ones: Capaldi utters both David Tennant’s famous “I don’t want to go!” and Matt Smith’s “I’ll always remember when the Doctor was me!” All of this leads to the biggest easter egg of all: the TARDIS takes the Doctor face-to-face with, himself. The final scenes of the episode find Capaldi starring at the face of the very first Doctor, originally played by William Hartnell from 1963-1966, but now, here, played by David Bradley.

Where has the 12th Doctor encountered the 1st Doctor? Probably right before the 1st Doctor regenerated, too. As hardcore fans know, William Hartnell’s Doctor’s last adventure was in four-part serial “The Tenth Planet.” But because of Hartnell’s health at the time, the Doctor isn’t even in the third part of that serial. Now, it looks like Doctor Who will retroactively show us where the 1st Doctor was: hanging out with himself.

After an episode in which Missy and the Master tried to reconcile their differences and ended up killing each other; it’s telling that the story ends with the oldest Doctor coming face-to-face with the newest one. Like many Doctors before him, Capaldi’s Time Lord seems to fear change. But, because he’s not a villain like the Master, it seems that he and his very first self will have to work a few things out. Hopefully, these two will bro-down a bit on the whole saving Gallifrey thing.

Willian Hartnell as the First Doctor

Now that the impending Christmas special will clearly feature the 1st Doctor and the 12th Doctor being grumpy old Time Lords and having an adventure, fans will probably start wondering about what the show will be like when the Doctor finally does regenerate. With the series coming full circle back to the very first version of the character, Doctor Who has seemingly exhausted fueling the TARDIS exclusively on old-guy nostalgia. Which means after the two crankiest Doctors of all time sort out their issues, a new Doctor might start steering the TARDIS in a direction that hopefully, is firmly away from the past.


The final Peter Capaldi Doctor Who episode is still untitled, but will air on Christmas Day, 2017.

Photos via BBC