The episode begins with a flashback on Gallifrey when the Doctor and Susan first stole the TARDIS, and Clara tells him he is about to make a mistake. Back in the present, the Doctor has finally made his way to the prophesied Trenzalore for an adventure that spans his whole life. Madame Vastra, Jenny, and Strax have been captured by the Great Intelligence and his army of Whisper Men and taken to Trenzalore. The Doctor tells Clara that it is the one place a timetraveler must never go—his own grave.
The Great Intelligence plans to enter the Doctor's tomb (which also happens to be the corpse of his dead TARDIS), and the only key that will open it is the Doctor's true name. In this episode, we see the return of River Song, and she appears to be much older than we have ever seen her. Through a lot of techno-babble, Moffat explains that River's digital consciousness that was left in the Library's Data Core after she died in “Forest of the Dead” was able to project herself here where she speaks his name and opens the tomb. It was a bit awkward; however, I did appreciate that his name was spoken without the audience ever hearing it. She also alludes to the fact that a lot of time has passed for her since the adventure in the Library, and she has not seen the Doctor since then. It is quite possible that, during her time in the databanks, she has learned about this event and prepared for it, because it does not make since why she would give the Great Intelligence what he wants. Perhaps we will learn that there is a very specific reason why this must happen, but we have not learned that as of yet.
They enter the tomb and inside is the TARDIS control room. I do feel the need to say that I did lose my suspension of disbelief for a little bit at this point. I know it is insignificant, but this is his future TARDIS and yet it has the same design for the interior as now. So, we are supposed to assume that he will never change the desktop setting again or, for some inane reason, it reverted back to the one he is currently using. This should not bother me, but it did. In the center, where the console usually resides, there is a pillar of spindly, interwoven strands of light.
The Doctor describes the column as “the scar tissue of [his] journey through the universe.” This is his own personal timeline as he traveled in time. What seems strange is that we have seen dead Time Lords before, and this was not the case. Rassilon appeared as a sort of holographic ghost, Borusa was turned to stone, and the Master's ashes were kept in an urn. Also, it is a bit strange that it is so difficult to break into the Doctor's tomb, yet five (or more accurately four and a half) Doctors were abducted and dumped in Rassilon's tomb with much less effort.
Much of the episode was stuffed with filler and exposition to get to the climax where the bulk of the action occurred. At this point the Great Intelligence steps into the timestream with the intention to defeat the Doctor throughout his entire life like some sort of malevolent Dr. Samuel Beckett. As the Doctor lays dying, Clara jumps inside to rescue him. She has now spread echoes of herself across time so that she could save him throughout his life. This was a clever way to work in the previous Doctors. We saw her saving his life during his different regenerations. For some strange reason, we saw all of them except for the Eighth and Tenth Doctors. I read online that there is a scene with the Tenth Doctor that was cut in America but was transmitted to the rest of the world. This makes no sense at all—Americans adore David Tennant, so I have no idea why he would be omitted here exclusively. As for the Eighth Doctor, maybe his scene was cut as well, maybe they were not here because the actual actors who portrayed these two will return, or maybe there is another explanation . . . but I am getting ahead of myself.
I had always assumed that the reason Clara was scattered throughout history would be caused by her travels with the Doctor. We finally have the answer. By sending out her echoes she herself was destroyed. So, it is up to the revived Doctor to return the favor and save her. He enters his own timestream. He finds her and they are confronted by someone she does not recognize (played by John Hurt). The Doctor says that this was him in the past, and when she says she has now seen all the previous Doctors, he responds by telling her that this is version of him that broke his vows as the Doctor and was known by another name.
It does seem strange that this is immediately followed by text reading, “Introducing John Hurt as the Doctor.” John Hurt is a brilliant actor, and I do think he is a fantastic fit for the Doctor; however, it is a bit unclear where this regeneration fits in the Doctor's timeline. As far as I can tell, there only seems to be a couple possibilities where he could fit. He could be from before he took the name the Doctor, which would mean that this is his original body and when he regenerated into William Hartnell, he adopted the name of Doctor. Since we never saw the Eighth Doctor regenerate, this could just be the older version of that iteration. This would also explain why we did not see the Eighth Doctor in any of the flashbacks. Similar to this is that he could be between the Eighth and Ninth Doctors. This has been the most predominate rumor on the internet; however, I do not feel that this is very likely, as this actually disagrees with canon. If you remember back to “Rose,” there is a picture of the Ninth Doctor at the Titanic, and he is wearing the Eighth Doctor's costume—implying that this is shortly after regenerating. Also, if John Hurt is a separate regeneration after he started calling himself the Doctor, it does not make sense that when other races display all their knowledge of the Doctor (such as the Cybermen in “The Next Doctor” and the Atraxi in “The Eleventh Hour”). The only real way this could be explained is that no other races met this Doctor as he only lived during the Time War, which was sealed off from the rest of the universe. Speaking of the Time War, if this is either the Eighth Doctor or between Eight and Nine, this oath breaking probably refers to the events in the Time War. The final theory that I have is that this is the future regeneration known as the Valeyard. In “The Trial of a Time Lord,” we learned about an evil Doctor from after his 12th regeneration. I feel like this is the most likely possibility, as it does not retcon any canon, and the Great Intelligence even refers to the Doctor as Valeyard in this episode.
Despite being a weak series, I do think that this was Steven Moffat's best finale. I really do think that he is a great writer; however, he is much better at the standalone episodes. His larger, series-long arcs have a tendency to get a bit messy and convoluted. When Russell T. Davies was the head writer, he managed to take many seemingly unrelated narrative threads and tie them together in a streamlined conclusion. Moffat has just not been able to use the individual plots to come together in an interconnected climax, which has made his finales feel disjointed. But, being that this series did not have as much cohesion, he had less to juggle, which made the finale a bit simpler and kept it more cohesive.
The most enjoyable aspect of the episode is that it managed to span the Doctor's entire life, which allows the audience to reflect back on the past 50 years as he rexamines his past. The cliffhanger ending leaves us wondering what we will see in the 50th anniversary special. The Doctor and Clara are still trapped in his timeline. My ultimate hope is that the celebration extends beyond just the special and into the next series. It could be really interesting if they still have not escaped his timeline by the end of the special and Series 8 spans all of the Doctor's life. Each episode could focus on the Doctor reliving a previous adventure for a different regeneration, plus a few extras. Besides for just showing an episode for each of the 11 previous Doctors, there could be an episode about him as a child on Gallifrey, one focusing on a battle in the Time War, and then they could even show an adventure from the Doctor's future.