The Doctor's greatest in-universe fangirl returns from the dead to insult continuity, and we couldn't be happier.
For something that used to be such a central part of Doctor Who for so long back in the 1970s, it took the new series a while to hit its stride on the UNIT stories. If you don't need any background on this, feel free to skip to the next paragraph. UNIT was the United Nations Intelligence Taskforce, an early specimen of the kind of paramilitary anti-alien organizations you see on TV all the time now. The Doctor, particularly the third one, spent quite a bit of time acting as the organization's scientific advisor, which, after protector of Trenzalore, is probably the closest thing he's ever had to an official job title (Lord High President of Gallifrey runs a distant third, with President of Earth now making a late entry). UNIT's British leader was Brigadier Alistair Lethbridge-Stewart, whom I've covered at length before.
In the modern Who era, UNIT is now the "Unified Intelligence Taskforce," which suggests that the U.N. has maybe become as politically charged a concept in the U.K. as it has here in the past few decades. In the Russell T. Davies era, the Doctor occasionally interacted with the new UNIT through a forgettable series of red berets and empty uniforms. It took Kate Lethbridge-Stewart, the Brigadier's daughter, to provide a face for UNIT that would stick. Not that things are looking so great for her right now, but that's not the point.
In any case, KLS would soon be upstaged by the Doctor's sort-of successor in UNIT's scientific division, a young woman known only as Osgood. Introduced in the 50th-anniversary special "The Day of the Doctor," this character sported a lab coat, clunky black glasses, and an asthma inhaler. Really, the only more effective "nerd" signifier she could have been saddled with was a long, multicolored scarf. So of course she had one of those too. Osgood was a vulnerable character for a number of reasons, including some personal insecurities that were exploited by the shapeshifting Zygons, particularly the one that took her shape. But she turned it around, tripping up her enemy with the aforementioned scarf. It's good for taking down bad guys as well as fourth walls, it turns out.
When Osgood returned in last season's finale, "Death in Heaven," she had updated her sartorial tribute to a bow tie in honor of the eleventh Doctor. "Bow ties are cool," she quoted back to his current version. For the Doctor's part, he appreciated not only Osgood's shout-out, but her intelligence and resourcefulness as well. Enough, in fact, to invite her to join him on the TARDIS. Which is a pretty big deal. The Doctor doesn't ask just anyone to join him; it only seemed that way last season.
Obviously that didn't work out, because in a scene that was by far that episode's most riveting, Missy first toyed with Osgood and then reduced her to dust. As Steven Moffat said at the time, "Osgood was the one we threw on the fire to make the Master burn brighter." How soon we forget that the Master once deleted a third of the universe.
Indeed, that death hurt. It was enough to make us pretty mad at the Master's latest incarnation, and want her to lose. A lot. Because like few other Doctor Who characters have been, Osgood was us.
This is not to say that viewer-surrogate characters on Doctor Who are a new thing. Quite the contrary, in fact. Since day one, one of the primary functions of the Doctor's companions has been to give him somebody to explain things to so that we viewers could follow along. Back before companions started getting things like character arcs in the show's third decade, that was pretty much all they got to do. Previous attempts to create characters that fans could directly relate to resulted in companions like Adric, and now everyone's favorite Adric story is the one where he gets killed off.
But Osgood was different. Osgood was a fan, one who wears her fandom on her sleeve (or, more accurately, around her neck). And she was a fan who was going to get to travel in the TARDIS, like every fan dreams of doing. But then oops, not so much.
Of course, while Steven Moffatt is terrible about killing off beloved characters, he's even worse, if that's the word, about bringing them back. Just ask Rory Williams. Or better yet, ask Osgood.
But that's a bit unfair. Missy did kill Osgood, to be sure. But as we were reminded at the opening of tonight's episode, she only killed one of the Osgoods. There was the original one and the Zygon copy, but the surviving Osgood isn't saying which it was. Even the late Osgood's epitaph is a simple "My Sister," boldly emblazoned on a rather large monument for someone whose coffin is probably a salt shaker.
So far, the Osgood we've still got hasn't had a chance to do much other than hide, huff, and get rescued by the Doctor while continuing to sport certain of the more idiosyncratic aspects of his long fashion history. But it's clear she takes her new gig seriously. Back around the first time we met Osgood, the tenth and eleventh Doctors forced the negotiation of a peace treaty between humanity and twenty million Zygons living in secret on Earth, disguised as humans. Which was a terrible idea, even coming from someone like me who is almost as pacifist as the Doctor is. But both Osgoods were determined to make it work. Even now, Osgood refuses to answer the direct question from her idol: which one is she? Because the question is beside the point.
And in Part 2 of the current two-parter, we can probably expect Osgood to step up and do something actively awesome. You can see she's got it in her. Whether that entails turning out to be the "hybrid" from the prophecy that the Doctor has been stressing out about all season, or just a simple and straightforward saving of the world, or even (worst-case scenario) a secretly rogue Zygon, I fully expect it to be more interesting than whatever plays out with evil-doppelganger Clara.
And if she somehow ends up on the TARDIS after all, I'll be the last one to complain.