Doctor Who is a funny phenomenon. (It’s often a funny TV show too, but let’s look at the phenomenon first.) Fifty years old as of this weekend, it’s enjoying a heavily promoted anniversary period, and while a lot of the current level of publicity has been driven by the BBC, it’s a show that inspires a degree of devotion from its adherents that’s unusual even in the world of science fiction.

Part of that is down to its two-part history: the original show, which ran for over three decades before petering out into low-budget irrelevance and a misguided attempt at a U.S.-led revival, and the new show, which launched in a blaze of glory in 2005 and is still going strong, despite sometimes iffy quality (something the show has always endured). Fans of the former are mostly fans of the latter, but fans of the latter aren’t always aware of the former.

Befitting its status as a celebration of all 50 years of the show, the 50th anniversary special, The Day of the Doctor, does its damndest to bridge that gap.

When the show was relaunched, one key element was altered: rather than being one of a race of time travellers, the Doctor instead became the last of them. More than that, it was revealed that he was responsible for their doom, together with that of their archenemies. This had the double effect of making the Doctor unique and adding a melancholy tone to his character that quality actors like Christopher Ecclestone and David Tennant were able to mine to good effect.

So for writer Steven Moffat to not only reveal this hinted-at element of the Doctor’s history in detail but also to effectively rewrite it during The Day of the Doctor was suitably ambitious. For him to succeed so thoroughly was a delight. Inevitably for a show with as convoluted a timeline as Doctor Who, there are some very visible plot holes and seams, but on the whole it makes for a thrilling adventure.

If The Day of the Doctor manages to bridge the gap between old and new though, it does so using the materials of the new. There are plenty of hat-tips and Easter Eggs relating to the old show embedded in the episode, but with the exception of a rather odd cameo towards the end, none of the actors who played the role in the old series make a showing (they did, however, get a cameo-filled anniversary special of their own).

Despite the hopes of some of the old-time fans, this was clearly the best choice. The old actors look nothing like they did when they played the role, and Moffat makes the absolute most of the three Doctors he has to play with (Tennant, Matt Smith and a war-weary John Hurt), making their commonalities and differences central to the unfolding of the plot.

The result is a special that’s all about the show itself, and all the more satisfying for that. I was lucky enough to see it in the cinema, where I was able to enjoy some very decent 3D effects and the reaction of the crowd around me to every grace note of the script and special effects. So many people there were not only dressed for the event but also knew all the show lore, resulting in laughter and applause in all the right places.

Those cinema showings may have been a gift to those fans whose love of the show extended back beyond the 2005 revival, but they weren’t solely enjoyed by them. The show is now bigger and deeper than it used to be, and the fan base is global in a way that only the Internet could allow.

With The Day of the Doctor, Steven Moffat not only celebrates the first 50 years of the show, tying together all of its constituent parts, he also ties a bow on the show as it has been since the relaunch. With a new Doctor in the form of Peter Capaldi incoming at Christmas, The Day of the Doctor strikes the right note: a celebration of all that has come before together with an opportunity to enjoy something new.