The “War Doctor” is about to trigger the Moment-which will destroy Gallifrey and the Dalek fleet surrounding it-in a farmhouse on the planet (possibly his old house). However, the Moment is sentient-with a conscience-and an interface, which manifests itself as his future companion-Rose Tyler. It wants to have him take a look at what his future will be if he pushes the button.
Meanwhile, the current Twelfth Doctor, Clara, and UNIT, are investigating strange things at the British National Gallery art Museum. There’s been statues broken, and paintings that are now missing certain elements-and apparently broken out from the outside. To make things even more unusual, there’s a painting of Gallifrey in the Time War at the Museum-the Fall of Arcadia.
Meanwhile, at another point in the Doctor’s past, the Tenth Doctor is in Elizabethan times-with Queen Elizabeth. He decides to propose to her, hoping to uncover that she’s really a Zygon, a race of alien shape-shifters last encountered by the Fourth Doctor. However, she is the real Elizabeth-and soon the Doctor and Elizabeth find themselves pursued by the real Zygons-one of which was masquerading as her horse.
At this point, the Moment opens time portals that allow the Three Doctors to suddenly converge.
The Tenth and the Eleventh seem to get along well at least at first, but then the War Doctor-an incarnation they disavowed-joins them. They are also surrounded by Elizabeth’s men, and taken to the tower.
In the Tower of London, the Doctors converse, and discover that there’s a Zygon plot-that they’re basically imprisoning themselves in the paintings, to emerge in the future and take over UNIT’s Black Archive by impersonating them, where they keep a lot of the Alien stuff. Clara finds this out the hard way, but thankfully she’s able to use a time vortex manipulator to go to the past and rescue the three Doctors, saving them from having to make a completed calculation to modify their sonic screwdrivers to escape from the Tower (although the cell door, as it turns out, was unlocked anyway).
Marrying Elizabeth before he goes (which will ultimately lead to consequences in the past for him), the Doctors think of a plan to stop the Zygons. They ask a UNIT man to move the Fall of Arcadia painting into the Black Archive. Using the Zygon’s technology, they then meld with the painting and emerge from it as the Zygons face off with the UNIT people they are impersonating.
Kate-the leader of UNIT is about to set off a nuke to eliminate London if the Zygon’s don’t yield-she’d rather die than be invaded. However, the Doctors temporarily muddle the memories of both UNIT and the Zygons, confusing them as to which is real and who is the Zygon duplicate-and then goad them into trying to develop a peace treaty.
The War Doctor is impressed by his future selves’s ingenuity, and feels that he is now ready to do what must be done-end the Time War to save the many. But he doesn’t have to do it alone-as the Tenth and Eleventh, perhaps thinking they’ve misjudged their past self-stand with him.
But Clara doesn’t want them to go through with it. She thinks of the title “Doctor”-the Man who makes people better-and that this a destructive act totally uncharacteristic of that. There must be another way.
There’s three of them. Three TARDISes. If they can do things right, if they can calculate a solution using their combined brainpower-they can save Gallifrey by moving it into another dimension, safe from the Daleks, while the Daleks will eliminate themselves in the crossfire. The Doctor didn’t destroy his planet in the past after all-he saved it.
The TARDIses surround Gallifrey-and not just them-the Doctor’s invited all this lives to this party to help complete the moving of the planet. Gallifrey stands.
There’s even an unexpected one-a Thirteenth Doctor-with some rather prominent eyebrows. More on him later, though…
After Gallifrey is safely transported to an unknown dimension, and the Dalek fleet destroys itself, the Doctors then return to the Gallifrey. Now, the War Doctor can confidently call himself the Doctor. His future incarnations-the Ninth, Tenth, and the first half of the Eleventh’s life will still live with the guilt of thinking they actually destroyed it, as the Doctors often do not retain memories as their timelines cross. They’re unsure where Gallifrey is, or how safe it is, but at least they tried and didn’t intentionally destroy it like they thought they did.
His purpose fufilled, the War Doctor regenerates into his “ninth” self, the Doctor we met at the beginning of the new series:
After the Doctors say their farewells, and the Eleventh is alone in the Gallery while Clara heads out for a bit; The Doctor wanders if one day he’ll retire, and maybe become a curator. A booming voice echoes from the Gallery: “You know, I really think you might…”
The man is the Gallery’s curator, but to the Eleventh Doctor, he bears an uncanny resemblance to an older version of his Fourth incarnation. He reveals that the painting’s title is Gallifrey Falls No More, that the Doctor will perhaps eventually find and return to his home planet-and also strongly hints that he is the Doctor, who has somehow re-regenerated into an ‘old favorite’ and retired to becoming a curator.
As he reenters the TARDIS-free of the guilt of the Time War and his unresolved past=and now, with new hope for the future-the Doctor dreams of returning with all his incarnations.
Clara sometimes asks me if I dream. Of course I dream, I tell her. Everybody dreams. But what do you dream about, she’ll ask. The same thing everybody dreams about, I tell her. I dream about where I’m going. She always laughs at that. But you’re not going anywhere, you’re just wandering about.
That’s not true. Not any more. I have a new destination. My journey is the same as yours, the same as anyone’s. It’s taken me so many years, so many lifetimes, but at last I know where I’m going.
Where I’ve always been going. Home, the long way round.