WARNING: This review contains spoilers

As the 9th Doctor might say, that was fantastic. Just fantastic.

It took me a while to realize exactly what Steven Moffat was going for in “The Day of the Doctor,” the landmark 50th Anniversary special of Doctor Who. Three Doctors – one current, one old, and one very new to the viewer – sharing quips, staring at 3D paintings, snogging multiple versions of Queen Elizabeth I, and battling the relatively-obscure Zygons across time and space is all well and good, if a little par for the course (for Doctor Who, at least), but underlying all the humor and mayhem was something much darker, much deeper, and much more intriguing: A complex existential character study of the Doctor himself, centered on John Hurt’s ‘War Doctor’ character as he contemplates doing what we know – or think we know – he eventually will.

It hit me during one of the special’s very best scenes: The War Doctor, trapped together with the Tenth (David Tennant) and Eleventh Doctor (Matt Smith) in the Tower of London, begins questioning his future selves on the decision they believe he has already made, to wipe out all Time Lords and Daleks alike in order to end the destructive Time War. The Eleventh Doctor has tried his best to forget about it. The Tenth is openly haunted. All three start arguing about their shared guilt and the ways in which they have tried (and failed) to cope with it, and the result is one of the most dramatically fascinating scenes that the modern series, at least, has ever delivered.

That is also “The Day of the Doctor” in a nutshell. The Eleventh Doctor ultimately wound up being the focal point of the episode – as well he should be, since Matt Smith is the current reigning Doctor – but for much of its runtime, the special is really the War Doctor’s story, a tale set across many locations in time and space but that is entirely framed within the time this ‘forgotten’ incarnation spends contemplating the decisive blow of the Time War. “The Day of the Doctor” is far from the first Doctor Who anniversary event that brought multiple incarnations of the character together – see “The Three Doctors,” “The Five Doctors,” and “The Two Doctors” for reference – and while Steven Moffat certainly looked to those specials for comedic inspiration – the War Doctor’s disapproval of Ten and Eleven is wonderfully reminiscent of William Hartnell’s scenes in “The Three Doctors,” for instance – the presence of multiple Doctors here had a more dramatic intent than previous reunions. Getting to interact with these future versions of himself is a gift to the War Doctor, a reprieve from his wartime deliberations that allows him to existentially analyze the fallout of his decision. Asking oneself if one can live with a terrible misdeed is one thing – actually encountering the evidence first hand is another matter entirely, and something that only Doctor Who, in its infinite inimitability, could tackle.

And if that was all “The Day of the Doctor” was – a repressed incarnation of the Doctor preparing himself for the ultimate sin by watching two future selves go through the motions of a relatively standard Doctor Who adventure, which is what all the material with the Zygons really boiled down to – I would have enjoyed it perfectly fine. The adventure is a slight one, overall, but it delivered some very good moments, especially in the interplay between Queen Elizabeth(s) and a characteristically in-over-his-head Tenth Doctor. Nevertheless, the point here was the War Doctor deliberating whether or not this was a choice he could make, and the Tenth and Eleventh Doctors struggling to accept this repressed incarnation as a part of themselves, and I found it all extremely thematically compelling, if not necessarily revolutionary.

But the episode shifts into an unexpected higher gear in its last twenty minutes or so, when the Eleventh Doctor, bearing the weight of everything his prior incarnations have experienced, chooses to rewrite his own history, giving both himself and the other Doctors in the room a real shot at redemption for the crime eating away at all of them. It is a spectacular, provocative climax, one that pays off on the episode’s themes of existential guilt in a way only Doctor Who could: through some exciting, confusing, and wildly invigorating fourth-dimensional manipulations, the boldest and most brilliant of which is to use the Doctor’s entire long lifespan – and all thirteen of his incarnations, past and future (*) – as the key to saving Gallifrey.

(*) I had been wondering if Peter Capaldi, the 12th Doctor-to-be, would show up in this episode, and the moment in which he does is just perfectly executed, timed precisely enough to make viewers cheer with excitement, but kept brief enough to maintain the mystery for his eventual introduction.