First broadcast 26 June 2010.

The TARDIS has exploded. The Doctor (Matt Smith) has been imprisoned inside history’s most impenetrable prison cell. Amy Pond (Karen Gillan) has been shot dead by her fiancée Rory Williams (Arthur Darvill) – who turns out to be an Auton. On top of everything else, the universe just ended.

Doctor Who‘s fifth 21st century season ends with a complicated, time-travelling, and oddly miniscule epic that brings Matt Smith’s entire 13-episode debut run to a close. Rewatched some years after the fact, and it feels like one of the most essentially ‘Steven Moffat’ episodes that Moffat ever devised. It also feels as if it has aged remarkably well. Upon its initial broadcast it felt a little too frantic and complex for its own good, with a hand-waved fairy tale ending. Sure, it’s still a fairy tale ending, but in an entire season based on the idea that we are all in the end just somebody else’s story, it is difficult to imagine a more perfect conclusion than this.

Doctor Who has historically used time travel as a magic door: it’s simply been a means of the Doctor to get to a new adventure. With his Season 3 episode “Blink” Steven Moffat made time travel a core aspect of the story, and in Season 4 his “Silence in the Library” two-parter played with making the Doctor’s future a key component of winning in his present. “The Big Bang” doesn’t simply use time travel to inform the story; it uses it to derive the nuts-and-bolts plot. With the Doctor jumping back and forth along his own timeline, it breaks a lot of expected narrative rules and turns what might have been desperate end-times drama into a genuinely amusing sort of screwball comedy.

The time-travelling shenanigans enable the episode to criss-cross the entire 13 episode length of the season, pulling it all into a unified shape that had never been achieved before. As showrunner, Russell T Davies had included vague foreshadowing code-words – “Bad Wolf” in one season, “Mr Saxon” in another, but as his replacement Moffat takes things to an entirely separate level. The young Amelia Pond of “The Eleventh Hour” returns in a manner that book-ends the entire year. An apparent continuity error from “Flesh and Stone” turns out to be a deliberate and heart-breaking bit of foreshadowing.

And then the Doctor dies saving the universe. It’s not a fake-out, and while he does obviously get returned to existence in a beautifully staged climax, Moffat really does manage to have his cake and eat it too. It is a beautiful farewell, and wonderfully performed by Matt Smith. When he comes back to life, it is such a wonderful moment that it doesn’t feel as inevitable as it obviously was.

“The Big Bang” is bold, impressively plotted and highly original television. It was not the season finale I ever expected. It turned out to be much, much stranger – and overwhelmingly better.

To be honest, I do not feel Season 5 gets the respect it is owed for just how new and fresh it manages to make the series. Despite a lower production budget than the immediately previous years, it generally looks much glossier and more cinematic. The average strength of the individual episodes is arguably as high as the 21st century series ever had. 13 episodes in all, and there is only really one of them that feels actively bad.

The only tinge of regret I feel is the knowledge that, when originally developed, this was intended to be the 10th Doctor’s last year instead of the 11th’s first: that the ‘raggedy man’ Doctor who first encounters Amelia Pond was going to be a season finale 10th Doctor, on his way to death from “The Big Bang”. It would have been a wonderful loop – so emotive and ‘timey wimey’. It would have been a much more exciting curtain call for David Tennant’s Doctor than the one he got.

Then again, Matt Smith’s Doctor is such a breath of fresh air here. It is difficult to be anything other than delighted. Was this the best year of Doctor Who since the revival? I might have to ponder this a little further, but I suspect it very probably was.